View allAll Photos Tagged nCoV
Bunin: Chopin Etude, Op. 10, No, 12
www.youtube.com/watch?v=q0h1J0pWENw
An American living in China talking about the nCoV
www.youtube.com/watch?v=L5rhyBKJXb4
On the Death of Dr. Li
www.youtube.com/watch?v=b-Fy80yHYQo&t=9s
*
Milstein - Meditation from Thais - Massenet
www.youtube.com/watch?v=ZEi-yPF2w1k
Heifetz plays Schubert Fantasie
www.youtube.com/watch?v=MqNVUGbsdzg
www.youtube.com/watch?v=zwPe89kXCJA
Ponce Estrellita
www.youtube.com/watch?v=rOIL8mGeOio
Milstein was also a favoured student of Auer like Heifetz, he even furthered his studies with Sarasate's, the Tsar of Violin, subsequently. His career was nonetheless eclipsed by Heifetz for whatever reason and despite the fact that many people prefer Milstein when coming to classical pieces.
Erica Morini - Tartini - Largo / Allegro commodo
Charlie and I are stuck home with #COVID, so pardon the random outtake. We both tested positive yesterday, so 10 days #quarantine to go. He is too young for the vaccine and sick. I am #vaccinated and, so far, asymptomatic.
I think most people should get vaccinated, but won't engage in arguments about it. I am sharing this personal thing hoping that my Flickr folks will just give it some thought, if they haven't already.
O Sole Mio, Carlo Bergonzi
www.youtube.com/watch?v=0nNxw7c55Mk
Bunin: Debussy - Arabesque No. 1 in E major
www.youtube.com/watch?v=GStfo_f4L0g
An American living in China talking about the nCoV
www.youtube.com/watch?v=L5rhyBKJXb4
On the Death of Dr. Li in Wuhan
www.youtube.com/watch?v=b-Fy80yHYQo&t=9s
Toscha Seidel - Grieg Violin Sonata #3, Mvt 3
www.youtube.com/watch?v=anTp1BExGes
Raoul Koczalski : Chopin
www.youtube.com/watch?v=fcV3P6zS30Q
www.youtube.com/watch?v=xhfmiuVSnDw
www.youtube.com/watch?v=dFSPMrxTgdk
www.youtube.com/watch?v=au33_fvyJng
www.youtube.com/watch?v=elTSwjBY8nQ
www.youtube.com/watch?v=sOHg33Shwl8
www.youtube.com/watch?v=7fprBFVoMeU
www.youtube.com/watch?v=fmRMyRYYGtQ
Tschaiovsky
www.youtube.com/watch?v=Ugn1MPF-T84&list=RDV_22HZ7T_F...
Scriabin
www.youtube.com/watch?v=eHPFrCJP6c4&list=RDsOHg33Shwl...
Schubert-Liszt
www.youtube.com/watch?v=V_22HZ7T_FQ&list=RDV_22HZ7T_F...
*
In Conversation With: Toscha Seidel
"Studying with Professor Auer was a revelation. I had private lessons from him, and at the same time attended the classes at the Petrograd Conservatory. I should say that his great specialty, if one can use the word specialty in the case of so universal a master of teaching as the Professor, was bowing. In all violin playing the left hand, the finger hand, might be compared to a perfectly adjusted technical machine, one that needs to be kept well oiled to function properly. The right hand, the bow hand, is the direct opposite—it is the painter hand, the artist hand, its phrasing outlines the pictures of music; its nuances fill them with beauty of color. And while the Professor insisted as a matter of course on the absolute development of finger mechanics, he was an inspiration as regards the right manipulation of the bow, and its use as a medium of interpretation. And he made his pupils think. Often, when I played a passage in a concerto or sonata and it lacked clearness, he would ask me: 'Why is this passage not clear?' Sometimes I knew and sometimes I did not. But not until he was satisfied that I could not myself answer the question, would he show me how to answer it. He could make every least detail clear, illustrating it on his own violin; but if the pupil could 'work out his own salvation' he always encouraged him to do so.
"Most teachers make bowing a very complicated affair, adding to its difficulties. But Professor Auer develops a natural bowing, with an absolutely free wrist, in all his pupils; for he teaches each student along the line of his individual aptitudes. Hence the length of the fingers and the size of the hand make no difference, because in the case of each pupil they are treated as separate problems, capable of an individual solution. I have known of pupils who came to him with an absolutely stiff wrist; and yet he taught them to overcome it.
HOW TO STUDY
"Scale study—all Auer pupils had to practice scales every day, scales in all the intervals—is a most important thing. And following his idea of stimulating the pupil's self-development, the Professor encouraged us to find what we needed ourselves. I remember that once—we were standing in a corridor of the Conservatory—when I asked him, 'What should I practice in the way of studies?' he answered: 'Take the difficult passages from the great concertos. You cannot improve on them, for they are as good, if not better, as any studies written.' As regards technical work we were also encouraged to think out our own exercises. And this I still do. When I feel that my thirds and sixths need attention I practice scales and original figurations in these intervals. But genuine, resultful practice is something that should never be counted by 'hours.' Sometimes I do not touch my violin all day long; and one hour with head work is worth any number of days without it. At the most I never practice more than three hours a day. And when my thoughts are fixed on other things it would be time lost to try to practice seriously. Without technical control a violinist could not be a great artist; for he could not express himself. Yet a great artist can give even a technical study, say a Rode étude, a quality all its own in playing it. That technic, however, is a means, not an end, Professor Auer never allowed his pupils to forget. He is a wonderful master of interpretation. I studied the great concertos with him—Beethoven, Bruch, Mendelssohn, Tschaikovsky, Dvoøák, the Brahms concerto (which I prefer to any other); the Vieuxtemps Fifth and Lalo (both of which I have heard Ysaye, that supreme artist who possesses all that an artist should have, play in Berlin); the Elgar concerto (a fine work which I once heard Kreisler, an artist as great as he is modest, play wonderfully in Petrograd), as well as other concertos of the standard repertory. And Professor Auer always sought to have us play as individuals; and while he never allowed us to overstep the boundaries of the musically esthetic, he gave our individuality free play within its limits. He never insisted on a pupil accepting his own nuances of interpretation because they were his. I know that when playing for him, if I came to a passage which demanded an especially beautiful legato rendering, he would say: 'Now show how you can sing!' The exquisite legato he taught was all a matter of perfect bowing, and as he often said: 'There must be no such thing as strings or hair in the pupil's consciousness. One must not play violin, one must sing violin!'
© Leanne Boulton, All Rights Reserved
Street photography from Glasgow, Scotland.
Previously unpublished shot from November 2018.
The Bank of England has just risen interest rates to 3%, the highest level for 14 years, in the run up to a winter of extortionate fuel prices and inflated food costs. We are forecast to be facing the longest recession since reliable records began, 100 years ago!
Inflationary pressures reported by the Bank of England include the Covid pandemic and the war in Ukraine as the BBC have reported. They also mention, which is neglected by mainstream media, that there are UK specific pressures (i.e. Brexit and the loss of benefits with our greatest trading partner). Also reported, significantly, is a large reduction in the labour workforce. More so than expected and a large increase since the last report from the Bank of England and they specifically mention that the vast majority is due to long term sickness. The US recently also reported that workplace productivity is down massively since pre-pandemic levels.
This is what 'living with Covid' means. Covid causes permanent internal damage and a conservative estimate by The Lancet is that "at least 145 million people worldwide have long COVID...". This is why China is pursuing a zero Covid strategy. They are well aware of the long-term damage to the labour workforce by SARS-nCov-2. Coronavirus is akin to a combination of SARS(1) and AIDS. The comments about airborne AIDS in early social media were not incorrect. This virus not only causes direct damage, it destroys T-cell protections in our immunity and leaves you incredibly vulnerable to further infections, with the same mechanism that occurs in HIV/AIDS. The virus shares some RNA of HIV in itself and this was evident from the start.
It doesn't take a genius to work out what this is doing to the workforce and China will emerge as a global powerhouse if they continue the zero Covid path.
A huge number of people are going to suffer this winter. A lot of ordinary people trying their best to make ends meet. Meanwhile the rich get richer, pay less, avoid taxes and reap the benefits of a government more invested in that top 1% than the millions and millions of ordinary working people.
Very tough times ahead. Please stay safe in this crazy world my Flickr friends.
© Leanne Boulton, All Rights Reserved
Street photography from Glasgow, Scotland.
Facts matter.
The 'summer cold' you may be hearing about, especially with razorblade throat' symptoms is highly unlikely to be a cold or 'flu. It will most likely be Covid.
SARS-Cov-2 and Covid19 never went away. Testing diminished and reporting stopped. The deaths and long term damage did not stop.
Covid is airborne.
Social distancing and washing your hands will not protect you from Covid.
It will hang in the air, like smoke, for hours in an unventilated room.
You can catch it outside from people's breath.
Each infection increases your risk of developing permanent internal damage 'Long Covid'.
6 years of scientific data and over 500,000 peer reviewed studies published by the most illustrious and respected medical and scientific journals around the world show the extent of the damage that SARS2/Covid19 does to the body.
Just some of it includes lung scarring, vascular damage (the lining of your blood vessels), causes clots and micro-clots (strokes, heart attacks), brain damage in the form of 'brain fog' and 'cognitive deficit' where it actually reduces brain tissue mass and fuses brain cells together, and immune system damage in a similar way to HIV that leaves you open to greater impacts from other opportunistic viral, bacterial and fungal infections. This is the tip of the iceberg. Because of the way that SARS2 binds to and replicates within our cells it can cause damage to almost every single part of the body. Viral reservoirs of Covid have even been found in semen some 6 months post-infection. Covid is oncogenic too. It has been shown to accelerate and 'supercharge' some cancers.
Even mild and asymptomatic infection causes internal damage.
Lateral flow tests are unreliable. A positive result will always be correct but they produce a high percentage of false negatives because swabbing is not always done correctly and the test sensitivity is not high. You also need to test every day during your infection.
You are most infectious for two days before you even notice symptoms.
If you have lingering symptoms from an infection that was likely to be Covid, you have 'Long Covid'. The numbers are grossly undercounted as many people don't realise their ongoing issues are Long Covid. Despite that, new figures record over 6 million children in the USA have Long Covid. An estimated 400 million people worldwide.
You have a 10-25% chance of developing Long Covid with each infection. Unprotected you are likely catching Covid at least 3-4 times a year - rolling the dice every single time.
Deaths are grossly undercounted too. The estimated 23 million deaths worldwide is not even remotely close. Graphs show the extent of this. Excess deaths compared to pre-pandemic levels, deaths from heart attacks in working age people, strokes, pneumonia, cancer in younger age groups. All rising continuously since the start of the ongoing pandemic.
You can protect yourself.
Well fitting FFP2/3 (N95/N99) masks worn indoors and in crowded places are the best protection we have. Far-UVC light, filtration and ventilation indoors.
Surgical and cloth masks will do little to protect you and other people. They offer just a small degree of protection. Vaccination will reduce the risk of severe outcomes but it will not eliminate the risk.
Why do I share this from time to time?
Because I care.
Because I hate that disinformation and lies have dominated the discourse on Covid.
Because I don't want you to suffer Long Covid as I am.
I have just spent two weeks recovering from a single 3 hour photography trip into Glasgow during which I spent a lot of time sitting down and resting. I wanted to go into Glasgow today but I am still not recovered enough and I know, that when I do make it, I will suffer for it afterwards.
I don't want any of you to experience this.
Please take it seriously. You only get one chance to stay healthy. You will miss it when it's gone.
Thank you for reading this.
© Leanne Boulton, All Rights Reserved
Selfie captured on the streets of Glasgow, Scotland.
Today, 9th March 2025, there are events all across the United Kingdom marking a national Covid Day of Reflection.
At the London Covid Memorial Wall I just heard, on the news, a nurse say, "...just because Covid-19 isn't with us anymore..." and I have to speak up. Covid-19 never went away - the pandemic is not, and has never been, declared over. Covid-19 is still with us.
The 232,000 or so deaths recorded officially as attributed to Covid-19 in the UK is a grotesque undercount. It completely ignores deaths due to post-Covid sequelae.
SARS-nCOV-2 is an infection spread by respiratory aerosols (airborne) that hang in the air like smoke in a poorly ventilated space. It is not, however, primarily a respiratory disease. Covid-19 is a cardiovascular and neurogenic disease that also damages the immune system in a similar way as HIV.
Each single infection and re-infection (as it mutates so rapidly that we never gain lasting immunity) causes permanent internal damage that may not be immediately apparent to us.
I am certain that you or someone you know has lasting effects of Covid-19. Brain not quite as sharp as it once was? Short term memory problems you never used to have? Changes in personality? Angry outbursts? Problems concentrating? Can't find the words? Easily breathless? New onset of diabetes? Sudden tinnitus? Deterioration of eyesight? Erectile disfunction that they never used to have? The long-lasting and permanent damage caused by SARS2 is a very, very long list. This is just a snippet.
Most people don't realise they have 'Long Covid'. It's easier and less worrisome to explain it away. Normalcy bias is a human trait after all.
There are over 440,000 peer reviewed studies by the leading virologists, scientists and clinicians around the world all concerning the devastating effects that SARS2 has upon the human body.
You can see the effects in graphs of heart attacks in working age adults, long-term sickness rates, disability benefit claims and much more all ramping up from 2020 onwards. This is a mass disabling event that major financial markets and insurance actuaries are taking notice of already. A complete failure of public health.
You can protect yourself to a degree with FFP2/3 respirator masking, HEPA filtration of indoor air and adequate ventilation. We have the tools to reduce the burden of disease massively but governments and businesses opted to put the onus on you - by telling you to wash your hands - instead of cleaning the air in their buildings.
I have symptoms of Long Covid following one single infection in the last 5 years. I can't afford to get ill again with the chance of compounding what I already have to live with on a daily basis. So I mask indoors and in crowded spaces.
All of the great smiles in my shots I have captured while masking like this. Because a smile can be seen from behind a mask.
I am not anxious. I am not afraid of Covid-19. I am not afraid of death.
I am afraid of becoming even more disabled and I am aware and educated about Covid-19.
When you know; you know.
Take care my Flickr friends.
Isolation. Living with memories. Covid.
Nellie Vin ©Photography.
"Stay home and separate from others as much as possible."
www.cdc.gov/coronavirus/2019-ncov/your-health/isolation.html
CHE COSA SONO I CORONAVIRUS?
I Coronavirus sono una famiglia di Virus che possono causare diverse infezioni, dal comune raffreddore a malattie come la MERS (Sindrome respiratoria del Medio Oriente) e la SARS (Sindrome Respiratoria Acuta Grave).
CHE COS'E' UN NUOVO CORONAVIRUS?
Un nuovo Coronavirus (nCoV) è un nuovo ceppo di coronavirus che non è stato precedentemente mai identificato nell'uomo.
Il nuovo Coronavirus 2019, denominato SARS-CoV-2, è un virus a RNA rivestito da un capside e da un peri-capside attraversato da strutture glicoproteiche che gli conferiscono il tipico aspetto ‘a corona'. Fa parte della grande famiglia dei coronavirus ed è geneticamente collocato all'interno del genus Betacoronavirus, con un clade distinto nel lineage B del sub-genus Sarbecovirus così come due ceppi Sars-like non umani (pipistrelli).
La diffusione del SARS-CoV-2 potrebbe essere partita dal mercato del pesce di Wuhan, nella provincia cinese di Hubei. Informazione attualmente smentita da un gruppo di scienziati cinesi pubblicata sulla rivista Lancet.
La situazione è in costante evoluzione. L'ECDC pubblica ogni giorno un aggiornamento epidemiologico (www.ecdc.europa.eu/en/geographical-distribution-2019-ncov...)
CORONAVIRUS
Coronaviruses (CoV) are a large family of viruses that cause illness ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV). A novel coronavirus (nCoV) is a new strain that has not been previously identified in humans.
Coronaviruses are zoonotic, meaning they are transmitted between animals and people. Detailed investigations found that SARS-CoV was transmitted from civet cats to humans and MERS-CoV from dromedary camels to humans. Several known coronaviruses are circulating in animals that have not yet infected humans.
Common signs of infection include respiratory symptoms, fever, cough, shortness of breath and breathing difficulties. In more severe cases, infection can cause pneumonia, severe acute respiratory syndrome, kidney failure and even death.
Standard recommendations to prevent infection spread include regular hand washing, covering mouth and nose when coughing and sneezing, thoroughly cooking meat and eggs. Avoid close contact with anyone showing symptoms of respiratory illness such as coughing and sneezing.
16:03:13
April 25, 2020
Day 45
COVID-19 Update:
United States Confirmed: 946K
Recovered: 102K
Deaths: 53,418
Worldwide Confirmed: 2.87M
Recovered: 812K
Deaths: 202K
Source: www.cdc.gov/coronavirus/2019-ncov/cases-updates/cases-in-...
People Who Need to Take Extra Precautions:
www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/...
Please remember all the vulnerable people, the elderly and those who will struggle in this time of the Covid-19 virus.
Help those who are stuck inside having to self-isolate. Drop off groceries, pick up prescriptions. Call people or message them.
Give elderly relatives and neighbours a phone call or a message, or post a letter giving your telephone number. Remember especially the elderly who are alone and probably very lonely.
Don't be selfish and stock-pile.
We're all in this together.
Let's take care of ourselves and each other.
Artwork ©jackiecrossley
© All rights reserved. This image may not be copied, reproduced, distributed, republished, displayed, posted or transmitted in any form or by any means, including electronic, mechanical, photocopying & recording without my written permission. This image is not authorised for use on your blogs, pinboards, websites or use in any other way. You may not download this image without written permission from me. Thank you.
Floating Terrain Mountain by MattiaMc
by LuckyStock
Particles: Christopher Campbell on Unsplash
Man: Adobe stock
Listen and enjoy: The Beatles - Eleanor Rigby
MONITOR MADNESS! - THE AWARD TREE - Challenge # 192/a>
*VIVID VIRUS ART* Challenge 22.0
"White to Bright" challenge drawing by Anping Huang
Completed: March 27, 2022
Category: Begginer
CPM White to Bright Challenge
100% colored pencil
Prismacolor Premier color pencils on Stratchmore Colored Pencil paper 477-9.
Size: 9x12 inches
Covid-19 has been a big problem around the world, and it inspired me to draw the destruction it has caused.
The tombstone represents the teacup, the stack of toilet paper represents the cup, COVID-19 vaccine represents the mini cup, a Bat represents the angel, hand sanitizer represents the vase, and finally the owl skeleton represents the owl.
Covid bottle reference photo: media.istockphoto.com/photos/ncov-covid19-coronavirus-vac...
Covid 19 reference image: www.who.int/images/default-source/mca/mca-covid-19/corona...
The Kawasaki Kinkai Kisen Kaisha, Ltd.'s passenger ferry MV Silver Queen arrives at Daikoku Pier, Yokohama Port, Japan, Febryary 14, 2020, and the Daito Corporation's tug boat TB Yumihari assists MV Silver Queen entering the port.
The ship came to Yokohama Port at the request of the Japan Ministry of Defense and was used from February 15 to February 25 as an accommodation facility for Japan Self-Defense Force's officers dedicated to a life support mission for passengers waiting for the quarantine period until February 19 on the cruise ship MV Diamond Princess (IMO: 9228198, MMSI: 235103359) where COVID-19 outbreak occured.
The show must go on. Protest of the fairground owners against the Covid restrictions.
thewashingtonstandard.com/cdc-documents-no-quantified-vir...
Even the WHO now admits that the death rate is much lower than previously estimated.
In 2020, even Santa Claus wore a mask (to protect others AND himself from the transmission of the coronavirus that causes COVID-19).
For 2021: wishing you less coronavirus and more Laimingų Naujųjų Metų!
***************
▶ Photographer's note:
The phrase above is "Happy New Year," in Lithuanian. This photographer is a 3rd-generation Lithuanian-American.
***************
▶ Photo by Yours For Good Fermentables.com.
▶ For a larger image, type 'L' (without the quotation marks).
— Follow on Twitter: @Cizauskas.
— Follow on Facebook: YoursForGoodFermentables.
— Follow on Instagram: @tcizauskas.
▶ Camera: Olympus OM-D E-M10 II.
▶ Commercial use requires explicit permission, as per Creative Commons.
Please stay safe and well during these times of great stress due to Covid 19
Hoping people really take this seriously and stay home ...or if they go out that they use precaution...and to those who are in denial that they wake up...we all need to act now!
sorry for my absence...just has not really been my year. ..but i think of you often...and wish you all well.
i realize many have no choice and must work but there are many ways to keep work space safer... a few good sources to go to in case you are not sure:
www.cdc.gov/coronavirus/2019-ncov/community/home/index.html
www.cdc.gov/coronavirus/2019-ncov/index.html
www.cdc.gov/coronavirus/2019-ncov/specific-groups/high-ri...
www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/sympto...
www.cdc.gov/coronavirus/2019-ncov/prepare/get-your-househ...
love she wolf
Frankfurt Alte Oper
According to CDC (Centers for disease control and prevention) the corona virus could not be isolated until today.
thewashingtonstandard.com/cdc-documents-no-quantified-vir...
This is a difficult time, a pandemic, which can even be spread from pets to owners, sometimes. www.cdc.gov/coronavirus/2019-ncov/daily-life-coping/anima...
My hobby is photography.
CTV Regional Contact gave me 3 minutes on the local CTV News here: www.youtube.com/watch?v=3C2U_01ajdw
Mikey G Ottawa's 100 most interesting images as per Flickriver HERE: www.flickriver.com/photos/mikeygottawa/popular-interesting/
See Mikey G Ottawa's most popular Flickr Photo Albums HERE:
www.flickr.com/photos/mikeygottawa/albums
CBC Radio 1 gave me almost eight minutes. Listen here: www.youtube.com/watch?v=253iqLH82oA
Rogers Cable TV gave me 10 minutes on Camera Talk HERE:
Let's remember that it was a bright and warm day yesterday at this colder and gray rainy sunday ... and it will be great again next week ;)
Social distancing, also called “physical distancing,” means keeping space between yourself and other people outside of your home. To practice social or physical distancing:
Stay at least 6 feet (2 meters) from other people
Do not gather in groups
Stay out of crowded places and avoid mass gatherings
www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/so...
The wearing of face masks during the COVID-19 pandemic has received varying recommendations from different public health agencies and governments. The topic has been a subject of debate,[1] with various public health agencies and governments disagreeing on a protocol for wearing face masks. As of early May, 88% of the world's population lives in countries that recommend or mandate the usage of masks in public and 75+ countries have mandated the use of masks.[2] Debates have emerged regarding whether masks should be worn even when social distancing at six feet (2 meters),[3][4][5] whether they should be worn during exercise,[6] worn in the home to reduce viral load,[7][8] and whether there are mitigating factors.[9][7] Additionally, public health agencies of different countries and territories have often changed their recommendations regarding face masks over time.[10] Face masks have been a subject of shortages, and also been made compulsory in some countries.
Types of face masks, from least to most protective, include cloth face masks, medical (non-surgical) masks,[11][12] surgical masks, and filtering facepiece respirators such as N95 masks and FFP masks. Face shields and medical goggles are other types of protective equipment often used together with face masks.
Contents
1Types of masks
1.1Face shields
1.2Cloth masks
1.2.1Sterilizing and re-use
1.3Surgical masks
1.4Disposable filtering respirators
1.4.1Sterilizing and re-use
1.5Elastomeric respirators
1.6Powered air-purifying respirators (PAPRs)
1.7Novel face masks (research and development)
2Recommendations
2.1World Health Organization recommendations
2.2US Centers for Disease Control and Prevention
2.3China and Asia
3Rationale for wearing masks
4Shortages of face masks
4.1Early epidemic in China
4.2National stocks and shortages
4.3N95 and FFP masks
5The mask industry
5.1Manufacturing
5.2Distribution
6Culture
6.1Attitudes
6.2Fashion
7Mask use and policies by country and territory
8References
Types of masks[edit]
Small particles zigzag due to Brownian motion, and are easily captured. Large particles get strained out, or have too much inertia to turn, and hit a fiber. Mid-size particles follow flowlines and are more likely to get through the filter; the hardest size to filter is 0.3 microns diameter.[13]
Certified medical masks are disposable (except some faceshields). They are made of non-woven material. They are mostly multi-layer. Filter material may be made of microfibers with an electrostatic charge; that is, the fibers are electrets. An electret filter increases the chances that smaller particles will veer and hit a fiber, rather than going straight through (electrostatic capture).[13][14][15][better source needed][medical citation needed] Typically, efficiency of the filtering materials decreases when washed or used multiple times.[16]
Many medical masks are respirators; they are designed to protect the wearer. Surgical masks, on the other hand, are meant to protect others against infection transmission from the wearer (so called "source control").[17] Some respirators and masks have valves,[18] which let exhaled air out unfiltered. This makes them bad for source control.[19] It may, however, reduce inwards leakage, thus improving wearer protection.[18]
Face shields[edit]
Person wearing a face shield over a green surgical mask. A simple 3D-printed face shield: curved visor, drawstring lanyard, sheet of transparent plastic curved from side to side.
Person wearing a face shield and a surgical mask.
Main article: Face shield
It is not yet known whether face shields are effective at preventing disease transmission. They protect against splash and splatter. Cough simulation experiments show that they protect[18] the wearer[20] against large drops immediately after the cough, but do not keep out smaller aerosols. The longer it was after the simulated cough, the more particles found their way around. Because there is no evidence they prevent the wearer from getting ill, face shields are used with nose-mouth masks, and to protect nose-mouth masks, but use of face shields alone is not recommended.[18]
Cloth masks[edit]
Homemade cloth face mask
Sneezing. There is limited evidence that cloth masks can significantly reduce aerosol droplet dispersal.[18]
Main article: Cloth face mask
A cloth face mask is a mask made of a common textile, usually cotton, worn over the mouth and nose. Although they are less effective than medical-grade masks, many health authorities recommend that the general public use them because medical-grade masks are in short supply.[21][22]
They were routinely used by healthcare workers starting from the late 19th century until the mid 20th century. In the 1960s they fell out of use in the developed world in favor of modern surgical masks, but their use has persisted in developing countries.[23][24][25]
There were calls for research into the effectiveness of improvised masks even before the emergence of COVID-19, motivated also by past epidemics and modelling of likely mask shortages. However, little research has been done. There are no studies of the use of cloth masks by the general public, one study on the use of cloth masks in hospitals (by healthcare workers, not patients), and many controlled-setting/lab studies of cloth masks' effects on aerosols as of May 2020.[18]
Cloth masks are low-cost and reusable. They vary widely in effectiveness depending on material, fit/seal, and number of layers, among other factors. Unlike disposable masks, there are no legal standards for cloth masks. Fit is important (as with disposable masks). Measures to improve fit, such as an outer layer made from sheer nylon stockings or sheer tights around the head, reduce leakage.[18]
Improvised cloth masks seem to be worse than standard commercial disposable masks, but better than nothing. There is, however, little good evidence on them. A single study gives evidence that an improvised mask was better than nothing, but not as good as soft electret-filter surgical mask, for protecting health care workers simulating treating a simulated infected patient, regardless of whether "patient" or carers wore the mask.[18] Another study had volunteers wear masks they made themselves, to a pattern like that of a standard surgical mask, but with ties rather than earloops,[26] from cotton T-shirts, and found that the number of microscopic particles that leaked inside the homemade masks was twice the number that leaked into the commercial masks, and that the homemade mask let three times as many microorganisms expelled by the wearer escape (median averages). There is limited evidence that cloth masks can significantly reduce droplet dispersal.[18]
Cloth masks are commonly made with one layer, two layers, or two layers with a pocket for a removable-filter interlayer [18] (disposable surgical mask also have three layers, with the filter layer midmost[citation needed]). The CDC recommends more than one layer.[27] There is no research on the usefulness of a filter interlayer, as of May 2020. There were until recently no non-disposable materials designed for making masks (see end of paragraph). Common household fabrics which could be utilized (turned to a new use) as mask materials have been tested.[28][29][30][31] Cloth materials vary widely in filtration efficiency. Some cotton and polyester household fabrics have been found to compare with disposable surgical masks for dry particle filtering. Cotton T-shirt material, pillowcase material, and 70% cotton/30% polyester sweatshirt material are among the common materials that performed well in lab tests, with T-shirts preferred to pillowcases because it was thought that it would probably fit better. Teatowels and vacuum-cleaner bags were effective at filtering, but had a very high air resistance, so were not recommended. Scarves filtered poorly. Surgical sterilisation wrap, a polypropylene non-woven fabric made for wrapping sterilized things to keep them sterile, is designed to filter germs from the air. Using surgical sterilisation wrap to make masks, or as a filter interlayer in cloth masks, has been suggested. There are, however, no tests on using surgical sterilisation wrap for masks, as of May 2020.[18] Other suggested materials for filter interlayers include air filter materials used in ventilation, heating, and air conditioning, some of which are similar to rigid electret masks in the size ranges of particles they filter. Electrostatic cotton and non-woven, meltblown fabric are the conventional materials used in disposible masks, but are not readily available during the COVID-19 epidemic. A new type of filter, a washable electrostatic cotton filter, has been reported since the start of the pandemic; it is said to withstand repeated washing and folding.[18] It is made of electrospun nanofibers; flanking insulating blocks lay these into quasi-aligned nonwoven sheets, which are layered criss-cross to make a meshlike multilayer mask.[32][33] There is a need for research comparing how well these materials work.[18][34]
Sterilizing and re-use[edit]
There is no research on sterilizing and reusing cloth masks, as of May 2020.[18] The CDC recommends doffing the mask by handling only the ear loops or ties, placing it directly in a washing machine, and immediately washing your hands in soap and water for at least 20 seconds. They also recommend handwashing before donning the mask and again immediately after any time you touch it.[35]
There is no information on reusing a interlayer filter, and disposing of it after a single use may be desirable.[18]
Surgical masks[edit]
Main article: Surgical mask
A surgical mask
A surgical mask is a loose-fitting, disposable device that creates a physical barrier between the mouth and nose of the wearer and potential contaminants in the immediate environment. If worn properly, a surgical mask is meant to help block large-particle droplets, splashes, sprays, or splatter that may contain viruses and bacteria, keeping it from reaching the wearer's mouth and nose. Surgical masks may also help reduce exposure of the wearer's saliva and respiratory secretions to others.[36] A surgical mask, by design, does not filter or block very small particles in the air that may be transmitted by coughs, sneezes, or certain medical procedures. Surgical masks also do not provide complete protection from germs and other contaminants because of the loose fit between the surface of the face mask and the face.[36] However, in practice, with respect to some infections like influenza surgical masks appear as effective as respirators (such as N95 or FFP masks).[37] Surgical masks may be labeled as surgical, isolation, dental, or medical procedure masks.[36] Surgical masks are made of a nonwoven fabric created using a melt blowing process.[38][39]
Surgical masks made to different standards in different parts of the world have different ranges of particles which they filter. Similar-looking single-use masks are one-layer and only filter larger particles (e.g. Chinese standard YY/T0969 masks).[40][medical citation needed]
Disposable filtering respirators[edit]
An N95 mask
Main article: Mechanical filter respirator
An N95 mask is a particulate-filtering facepiece respirator that meets the N95 air filtration rating of the US National Institute for Occupational Safety and Health, meaning that it filters at least 95 percent of airborne particles, while not resistant to oil like the P95. It is the most common particulate-filtering facepiece respirator.[41] It is an example of a mechanical filter respirator, which provides protection against particulates, but not gases or vapors.[42] Like the middle layer of[citation needed] surgical masks, the N95 mask is made of four layers[18] of melt-blown nonwoven polypropylene fabric.[43][44][unreliable medical source?] The corresponding face mask used in the European Union is the FFP2 respirator.[45][46]
Hard electret-filter masks like N95 and FFP masks must fit the face to provide full protection. Untrained users often get a reasonable fit, but fewer than one in four gets a perfect fit. Fit testing is thus standard. A line of vaseline on the edge of the mask[47] has been shown to reduce edge leakage[18] in lab tests using manikins that simulate breathing.[47]
Sterilizing and re-use[edit]
Hard electret-filter masks are designed to be disposable, for 8 hours of continuous or intermittent use. One laboratory found that there was a decrease in fit quality after five consecutive donnings.[18]
Hard electret-filter masks are often reused,[citation needed] especially during pandemics when there are shortages. Infectious particles could survive on the masks for up to 24 hours after the end of use, according to studies using models of SARS-CoV-2;[18] In the COVID-19 epidemic, the US CDC recommended that if masks run short, each health care worker should be issued with five masks, one to be used per day, such that each mask spends at least five days stored in a paper bag between each use. If there are not enough masks to do this, they recommend sterilizing the masks between uses.[48] Some hospitals have been stockpiling used masks as a precaution.[49] The US CDC issued guidelines on stretching N95 supplies, recommending extended use over re-use. They highlighted the risk of infection from touching the contaminated outer surface of the mask, which even professionals frequently unintentionally do, and recommended washing hands every time before touching the mask. To reduce mask surface contamination, they recommended face shields, and asking patients to wear masks too ("source masking").[50]
Apart from time, other methods of disinfection have been tested. Physical damage to the masks has been observed when microwaving them, microwaving them in a steam bag, letting them sit in moist heat, and hitting them with excessively high doses of ultraviolet germicidal irradiation (UVGI). Chlorine-based methods, such as chlorine bleach, may cause residual smell, offgassing of chlorine when the mask becomes moist, and in one study, physical breakdown of the nosepads, causing increased leakage.[18] Fit and comfort do not seem to be harmed by UVGI, moist heat incubation, and microwave-generated steam.[18]
Some methods may not visibly damage the mask, but they ruin the mask's ability to filter. This has been seen in attempts to sterilize by soaking in soap and water, heating dry to 160°C, and treating with 70% isopropyl alcohol, and hydrogen peroxide gas plasma[18] (made under a vacuum with radio waves[51]). The static electrical charge on the microfibers (which attracts or repels particles passing through the mask, making them more likely to move sideways and hit and stick to a fiber[citation needed]) is destroyed by some cleaning methods. UVGI (ultraviolet light), boiling water vapour, and dry oven heating do not seem to reduce the filter efficiency, and these methods successfully decontaminate masks.[18]
UVGI (an ultraviolet method), ethylene oxide, dry oven heating and (highly toxic[citation needed]) vaporized hydrogen peroxide are currently the most-favoured methods in use in hospitals, but none have been properly tested.[18] Where enough masks are available, cycling them and reusing a mask only after letting it sit unused for 5 days is preferred.[48]
Elastomeric respirators[edit]
Main article: Mechanical filter respirator
Elastomeric full-face masks
Elastomeric respirators are reusable devices with exchangeable cartridge filters that offer comparable protection to N95 masks.[52] They were used as a substitute for N95 masks among shortages during the COVID-19 pandemic.[19]
The filters which must be replaced when soiled, contaminated, or clogged. These components may be hard to find amidst shortages; the filters may thus be sterilized, in a way that does not harm the filter, and re-used. In medical use, they must be cleaned and disinfected, as some germs can survive on them for weeks.[19]
Full-face versions of elastomeric respirators seal better and protect the eyes. If they have exhalation valves, then they are counterrecommended in settings where the unfiltered exhaled air might infect others (for instance, surgery). Fitting and inspection is essential to effectiveness.[19]
Powered air-purifying respirators (PAPRs)[edit]
A PAPR in a level-3 biosafety lab. Note waist pack and hose to blow air into headpiece.
Main article: Powered air-purifying respirator
PAPRs are expensive masks with a battery-powered blower that blows air through a filter to the wearer. Because they create positive pressure, they need not be tightly-fitted.[53] PAPRs typically do not filter exhaust from the wearer.[54] They are not generally designed for healthcare use, as of 2017.[17]
Novel face masks (research and development)[edit]
On 15 April 2020 scientists claimed to have developed a biodegradable material for face masks which is effective at removing particles smaller than 100 nanometres including viruses and has a high breathability.[55][56] Two Israeli companies reportedly have developed antiviral face masks – one of which is infused with antiviral copper oxide and zinc oxide nanoparticles, the other is made out of cotton embedded with accelerated copper oxide particles and a nanofiber textile.[57][58][59] Other Israeli researchers have developed a 3D-printed nanoscale fiber sticker coated with antiseptics which can be attached to a traditional mask for extra protection.[59] Other reseachers report that laser-induced graphene may be used to add self-cleaning and photothermal properties to face masks.[59] In March 2020 Jiaxing Huang became the first scientist to receive a $200,000 grant by the United States' National Science Foundation to develop a chemical which can be safely built into common face masks to make them protect against SARS-CoV-2 and self-sanitize passing droplets.[59][60]
Recommendations[edit]
Health organizations have recommended that people cover their mouth and nose with a bent elbow or a tissue when coughing or sneezing, and dispose of any tissue immediately.[61][62] Surgical masks are recommended for those who may be infected,[63][64][65] as wearing a mask can limit the volume and travel distance of expiratory droplets dispersed when talking, sneezing, and coughing.[66]
Masks have also been recommended for use by those who are taking care of someone who may have the disease.[65] The WHO has recommended the wearing of masks by healthy people only if they are at high risk, such as those who are caring for a person with COVID-19, though they also acknowledge that wearing masks may help people avoid touching their face.[65] Several countries have started to encourage the use of face masks by members of the public.[67]
As of May 2020, 88% of the world's population lived in countries where their government and leading disease experts recommended the use of masks in public places to limit the spread of COVID-19.[2]
World Health Organization recommendations[edit]
World Health Organization advice to the public in the context of COVID-19 endorsed the use of masks only under the following conditions:[68]
If you are healthy, you only need to wear a mask if you are taking care of a person with suspected 2019-nCoV infection.
Wear a mask if you are coughing or sneezing.
Masks are effective only when used in combination with frequent hand-cleaning with alcohol-based hand sanitizer or soap and water.
If you wear a mask, then you must know how to use it and dispose of it properly.
— World Health Organization
US Centers for Disease Control and Prevention[edit]
Guidance from the US Centers for Disease Control and Prevention on using and making cloth masks during the COVID-19 pandemic[69]
The United States Centers for Disease Control and Prevention (CDC) recommended in April 2020 that the general public wear cloth face coverings in public settings where other social distancing measures are difficult to maintain, such as grocery stores and pharmacies, especially in areas of significant community-based transmission, due to the significance of asymptomatic and pre-symptomatic disease transmission.[69][70]
In March 2020, the CDC recommended that if neither respirators nor surgical masks are available, as a last resort, it may be necessary for healthcare workers to use masks that have never been evaluated or approved by NIOSH or homemade masks, though caution should be exercised when considering this option.[71]
In March and April 2020, the CDC faced backlash over their earlier statements advising that most healthy people did not need to wear a mask. The earlier recommendations had been made to try to conserve supplies for medical professionals,[dubious – discuss][medical citation needed] but damaged the agency's credibility.[72][73][74]
In January 2020, there was no evidence on whether masks were useful for people who were not sick in a community setting.[75][dubious – discuss]
China and Asia[edit]
China has specifically recommended the use of disposable non-surgical medical masks by healthy members of the public,[11][76] particularly when coming into close contact (1 metre (3 ft) or less) with other people.[77] Hong Kong recommends wearing a surgical mask when taking public transport or in crowded places.[78][79] Thailand's health officials are encouraging people to make cloth face masks at home and wash them daily.[80] The Taiwanese, South Korean, and Japanese governments have also recommended the use of face masks in public.
When asked about the mistakes that other countries were making in the pandemic in March, the Chinese Center for Disease Control and Prevention director-general George Fu Gao said:
"The big mistake in the U.S. and Europe, in my opinion, is that people aren't wearing masks. This virus is transmitted by droplets and close contact. Droplets play a very important role − you've got to wear a mask, because when you speak, there are always droplets coming out of your mouth. Many people have asymptomatic or presymptomatic infections. If they are wearing face masks, it can prevent droplets that carry the virus from escaping and infecting others."[81]
Rationale for wearing masks[edit]
Queue to buy face masks in Hong Kong, 30 January 2020. Everyone in the line is already wearing a disposable medical mask.
File:Qualitative-Real-Time-Schlieren-and-Shadowgraph-Imaging-of-Human-Exhaled-Airflows-An-Aid-to-Aerosol-pone.0021392.s002.ogv
Shadowgraphs. Left, videos of the outer airflow during a sneeze, comparing different methods of covering one's mouth and nose (and none).[82] Right, conversation. Convection also shown.
Among the reasons cited by Chinese health officials for the wearing of masks, even by healthy individuals, are the following:
Asymptomatic transmission. Many people can be infected without symptoms or only with mild symptoms.[83]
Impossibility of appropriate social distancing in many public places at all times.[83]
Cost-benefit mismatch. If only the infected individuals wear a mask, they would possibly have a negative incentive to do so. An infected individual might get nothing positive, but only bear the costs such as inconvenience, purchasing expenses, and even prejudice.[83]
There is no shortage of masks in China, which has been producing 100 million masks per day since early March.[83]
Leading microbiologist Yuen Kwok-yung from the University of Hong Kong cites a large viral load in sputum and saliva of an infected person and asymptomatic cases as the reasons why even healthy individuals should wear a mask.[84][85]
According to Stephen Griffin, a virologist at the University of Leeds, "Wearing a mask can reduce the propensity [of] people to touch their faces, which is a major source of infection without proper hand hygiene."[86] The precautionary principle has also been cited by the British Medical Journal as a reason some may encourage universal face mask wearing.[87]
Asian health officials and experts have been promoting universal masking. For instance, Linfa Wang (a leading infectious disease expert who heads a joint Duke University and National University of Singapore research team) stated that masking is about "preventing the spread of disease rather than preventing getting the disease", remarking that the point is to cover the faces of people who are infected but do not know it, so it is imperative for everyone to wear one in public.[88]
Recent studies have suggested that the required six feet of social distancing is insufficient and based on debunked studies from the 1930s or error.[89][90][1]
Shortages of face masks[edit]
See also: Shortages related to the COVID-19 pandemic
Early epidemic in China[edit]
People in Wuhan lining up in front of a drug store to buy surgical masks.
A notice at a supermarket in Beijing, which says each person can only buy one pack of surgical masks and one bottle of 84 disinfectant liquid a day.
Chinese electronics manufacturers, such as BYD Electronic, began to produce surgical masks after the outbreak.
As the epidemic accelerated, the mainland market in China saw a shortage of face masks due to increased public demand.[91] In Shanghai, customers had to queue for nearly an hour to buy a pack of face masks; stocks were sold out in another in half an hour.[92] Hoarding and price gouging drove up prices, so the market regulator said it would crack down on such acts.[93][94] In January 2020, price controls were imposed on all face masks on Taobao and Tmall.[95] Other Chinese e-commerce platforms – JD.com,[96] Suning.com,[97] Pinduoduo[98] – did likewise; third-party vendors would be subject to price caps, with violators subject to sanctions.
By March China had quadrupled its production capacity (100 million masks per day).[83]
National stocks and shortages[edit]
In 2006, 156 million masks were added to the US Strategic National Stockpile in anticipation of a flu pandemic.[99] After they were used against the 2009 flu pandemic, neither the Obama administration nor the Trump administration renewed the stocks.[99] By 1 April, the US's Strategic National Stockpile was nearly emptied.[100][clarification needed]
In France, 2009 H1N1-related spending rose to €382 million, mainly on supplies and vaccines, which was later criticised.[101][102] It was decided in 2011 to not replenish its stocks and rely more on supply from China and just-in-time logistics.[101] In 2010, its stock included 1 billion surgical masks and 600 million FFP2 masks; in early 2020 it was 150 millions and zero, respectively.[101] While stocks were progressively reduced, a 2013 rationale stated the aim to reduce costs of acquisition and storage, now distributing this effort to all private enterprises as an optional best practice to ensure their workers' protection.[101] This was especially relevant to FFP2 masks, more costly to acquire and store.[101][103] As the COVID-19 pandemic in France took an increasing toll on medical supplies, masks and PPE supplies ran low, causing national outrage. France needs 40 millions masks per week, according to French president Emmanuel Macron.[104] France instructed its few remaining mask-producing factories to work 24/7 shifts, and to ramp up national production to 40 million masks per month.[104] French lawmakers opened an inquiry on the past management of these strategic stocks.[105] The mask shortage has been called a "scandal d'État" (State scandal).[106]
In late-March/early-April 2020, as Western countries were in turn dependent on China for supplies of masks and other equipment, China was seen as making soft-power play to influence world opinion.[107][12] However, a batch of masks purchased by the Netherlands was reportedly rejected as being sub-standard. The Dutch health ministry issued a recall of 600,000 face masks from a Chinese supplier on 21 March which did not fit properly and whose filters did not work as intended despite them having a quality certificate.[107][12] The Chinese Ministry of Foreign Affairs responded that the customer should "double-check the instructions to make sure that you ordered, paid for and distributed the right ones. Do not use non-surgical masks for surgical purposes".[12] Eight million of 11 million masks delivered to Canada in May also failed to meet standards.[108][109]
N95 and FFP masks[edit]
A woman in Ukraine wearing an FFP mask after masking in public places was made mandatory.
N95 and FFP masks were in short supply and high demand during the COVID-19 pandemic.[110][101] Production of N95 masks was limited due to constraints on the supply of nonwoven polypropylene fabric (which is used as the primary filter), as well as the cessation of exports from China.[43][111] China controls 50 percent of global production of masks, and facing its own coronavirus epidemic, dedicated all its production for domestic use, only allowing exports through government-allocated humanitarian assistance.[43]
In March 2020, US President Donald Trump applied the Defense Production Act against the American company 3M, which allows the Federal Emergency Management Agency to obtain N95 respirators from 3M.[112][113] White House trade adviser Peter Navarro stated that there were concerns that 3M products were not making their way to the US.[112] 3M replied that it has not changed the prices it charges, and was unable to control the prices its dealers or retailers charge.[112]
In early April 2020, Berlin politician Andreas Geisel alleged that a shipment of 200,000 N95 masks that it had ordered from American producer 3M's China facility were intercepted in Bangkok and diverted to the United States. Berlin police president Barbara Slowik stated that she believed "this is related to the US government's export ban."[114] 3M said they had no knowledge of the shipment, stating "We know nothing of an order from the Berlin police for 3M masks that come from China," and the US government denied that any confiscation had taken place and said that they use appropriate channels for all their purchases.[114][115] Berlin police later confirmed that the shipment was not seized by US authorities, but was said to have simply been bought at a better price, widely believed to be from a German dealer or China. This revelation outraged the Berlin opposition, whose CDU parliamentary group leader Burkard Dregger accused Geisel of "deliberately misleading Berliners" in order "to cover up its own inability to obtain protective equipment". FDP interior expert Marcel Luthe said "Big names in international politics like Berlin's senator Geisel are blaming others and telling US piracy to serve anti-American clichés."[116] Politico Europe reported that "the Berliners are taking a page straight out of the Trump playbook and not letting facts get in the way of a good story."[117] The Guardian also reported that "There is no solid proof Trump [nor any other American official] approved the [German] heist".[118]
Jared Moskowitz, head of the Florida Division of Emergency Management, accused 3M of selling N95 masks directly to foreign countries for cash, instead of the US. Moskowitz stated that 3M agreed to authorized distributors and brokers to represent they were selling the masks to Florida, but instead his team for the last several weeks "get to warehouses that are completely empty." He then said the 3M-authorized US distributors later told him the masks Florida contracted for never showed up because the company instead prioritized orders that came in later, for higher prices, from foreign countries (including Germany, Russia, and France). As a result, Moskowitz highlighted the issue on Twitter, saying he decided to “troll” 3M.[119][120][121] Forbes reported that "roughly 280 million masks from warehouses around the US had been purchased by foreign buyers [on March 30, 2020] and were earmarked to leave the country, according to the broker — and that was in one day", causing massive critical shortages of masks in the US.[122][123]
As more and more countries restricted the export of N95 masks, Novo Textiles in British Columbia had plans to become the number-one manufacturer in Canada.[124] AMD Medicom in Quebec also plans to become the second Canadian manufacturer of N95 masks, with a contract to supply the Government of Canada.[125]
The mask industry[edit]
Manufacturing[edit]
The government of Taiwan instituted a mask rationing system. With population of 24 million, Taiwan has been producing more than 10 million masks per day since March.
The U.S. National Guard sews facemasks
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As of 2019, mainland China manufactured half the world output of masks.[126] As Covid-19 spread, enterprises in several countries quickly started or increased the production of face masks.[127] Cottage industries and volunteer groups also emerged, manufacturing cloth masks for localised use. They used various patterns, including some with a bend-to-fit nosepiece inserts. Individual hospitals developed and requested a library of specific patterns.[128][129][130][131]
Distribution[edit]
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This section needs expansion. You can help by adding to it. (May 2020)
Some clinical stockpiles have proved inadequate in scale, and markets have expanded as non-medical consumers started obeying mandated mask-wearing or determined that masks might help or encourage them. Worldwide demand for face masks has resulted in masks shipping around the globe as a result of commercial transactions or of donations.[132]
Culture[edit]
A sign language interpreter (on the right) is wearing a transparent mask to allow lip reading.
Attitudes[edit]
In East Asian societies, a primary reason for mask-wearing is to protect others from oneself.[133][134] It is seen as a collective responsibility to reduce the transmission of the virus.[135] The broad assumption behind the act is that anyone, including seemingly healthy people, can be a carrier of the coronavirus.[134] A face mask is thus seen as a symbol of solidarity.[135] Elsewhere, the need for mask-wearing is often seen in an individual's perspective where masks only serve to protect oneself.[133]
Cultural norms and social pressure may also impede mask-wearing in public.[136] According to the Hong Kong doctor and infectious disease expert Joseph Tsang, the promotion of universal masking may resolve perceptions against mask-wearing, because mask-wearing is intimidating if few people wear masks due to cultural barriers, but if all people wear masks it shows a message that people are in this together.[88]
In the western world, the public usage of masks still often carries a large stigma,[133][135][137] as it is seen as a sign of sickness.[137] This stigmatization is a large obstacle to overcome, because people may feel too ashamed to wear a mask in public and therefore opt to not wear one.[138] Secondly, it is heavily racialized as an Asian phenomenon.[135] This has been reinforced in a lot of media discourses, where unrelated stories about the pandemic are often accompanied by imagery of Asian people in masks.[139] The focus on race has brought hostility towards Asians who are confronted with the choice to mask as precaution while they face discrimination for it.[140] However, there is also a divide within the western world, as seen in the Czech Republic and Slovakia where mass mobilization has occurred to reinforce the solidarity in mask-wearing since March 2020.[133]
On social media, there has been an effort with the #masks4all campaign to encourage people to use masks.[141] Mask-wearing has been called a prosocial behavior in which one protects others within their community.[142][143]
In the US, mask-wearing was politicized and is seen as a political statement by some people. Democrats were more likely than Republicans to say that they are wearing a mask when leaving home, 76% to 59% according to one poll.[144]
Fashion[edit]
Face masks have had an impact on fashion, with the masks themselves becoming a fashion statements, haute couture brands having pivoted to address both public health and aesthetic needs.[145][146][147][148]
Mask use and policies by country and territory[edit]
See also: COVID-19 pandemic by country and territory and National responses to the COVID-19 pandemic
Beijing Subway advises passengers to wear masks when taking trains
Argentina Argentina: After appearance of three asymptomatic cases, the capital Buenos Aires introduced compulsory masking since 14 April. Wearing a mask was made obligatory for everyone on public transit and everyone who contacts with the public in their position. Violators can face a fine. Authorities also prohibited the sale of N95 face masks to non-medical workers, suggesting the general public to use home-made masks instead.[149]
Austria Austria: Everyone entering a supermarket, a grocery store, or a drug store or using public transportation must wear a face mask, mandatory since 14 April.[150][151][152]
The Bahamas Bahamas: On 19 April, the prime minister announced that wearing a mask or covering one's face with clothing is mandatory in public. Employers must provide their employees who are serving the general public with masks.[153]
Bahrain Bahrain: The Kingdom made wearing face masks in public areas compulsory for citizens and residents as well as shop workers.[154]
Benin Benin: From 8 April, Benin's authorities began enforcing the mandatory wearing of face masks to halt the coronavirus.[155]
Bosnia and Herzegovina Bosnia and Herzegovina: Wearing a face mask is compulsory.[156][157]
Bulgaria Bulgaria: Bulgaria's government passed an order imposing an obligation to wear face masks on 30 March. The order was cancelled the next day and changed into a recommendation, due to legal complaints.[158]
Cambodia Cambodia: Many Cambodians started wearing face masks soon after the outbreak began in Wuhan. Businesses started to require customers to wear masks.[159]
Cameroon Cameroon: On 6 April, mayor of Douala announced that wearing a mask will be mandatory to slow the spread of coronavirus.[160]
Canada Canada: Since 6 April, health officials recommend wearing non-medical masks in situations where physical distancing from others is difficult (like buying groceries, or public transit).[161]
Chile Chile: From 8 April, Chilean Health Minister announced wearing a mask is mandatory in public transit.[162]
China China: Healthy individuals are advised to wear disposable medical masks in public places.[11][77] Some local governments require wearing masks when going outside. Shanghai makes wearing masks mandatory in public places.[163]
Colombia Colombia: In response to the most recent recommendations of the WHO, Colombia changed its policy on the use of masks and made it mandatory throughout the country for the use of public transport during the coronavirus emergency.[164]
Cuba Cuba: On 11 March, the government urged citizens to make their own masks, while the textile industry was drafted to fabricate them. People were advised to carry several cloth masks with them, depending on how many hours they plan to spend in public areas.[165] Later, wearing a mask was made mandatory.[166]
Czech Republic Czech Republic: Forbidden to go out in public without wearing a mask, or covering one's nose and mouth.[167]
Dominican Republic: Since 16 April, the use of face mask is mandatory in all public spaces and in the workplace.[168]
Democratic Republic of the Congo DR Congo: Since 20 April, wearing masks in the capital of Kinshasa is mandatory.[169]
Ecuador Ecuador: On 8 April, the Emergency Operations Committee (COE) decided to make face masks obligatory in public spaces.[170]
Ethiopia Ethiopia: The Council of Ministers approved a regulation that outlaws handshakes, and obligates the use of face masks in public places.[171]
France France: On 3 March, the government issued a degree announcing requisition of stocks of FFP2 and anti-splash masks until 31 May 2020.[172]
Gabon Gabon: On 10 April, the Gabonese government announced individuals in all parts of the country are required to wear masks in public to limit the spread of COVID-19.[173]
Germany Germany: On 31 March, city-county Jena, Thuringia, was the first large German city to introduce an obligation to wear masks, or makeshift masks including scarves, in supermarkets, public transport, and buildings with public traffic, from 6 April, very successfully. On 2 April, the Robert Koch Institute, the federal epidemic authority, changed its previous recommendation that only people with symptoms should wear masks to also include people without symptoms.[174][175] County Nordhausen, Thuringia, followed the example of Jena, since 13 April, several other cities later. German chancellor Merkel and state governors first gave "strong advice" to wear face masks in public from 20 April, Saxony made it mandatory from that day, Saxony-Anhalt followed from 23 April and (the rest of) Thurinigia from 24 April, finally the governors agreed to make it mandatory, so most other states followed from 27 April, except Schleswig-Holstein, from 29 April, and Berlin, where shops were excluded first, they were included from 29 April.[176]
Guinea Guinea: Guinean President Alpha Conde decided to make wearing masks compulsory.[177]
Honduras Honduras: From 7 April, Honduras President announced all citizens will now be required to cover their mouths when they are outside.[178]
Hong Kong Hong Kong: Members of the public are recommended to wear a surgical mask when taking public transport or staying in crowded places.[78]
India India: From 9 April, masking is compulsory in the state of Odisha. When leaving their home, people must cover their mouth and nose with masks or multilayered cloth (like handkerchief, dupatta, towel, etc.).[179]
Indonesia Indonesia: Citizens were ordered to wear face masks when they leave the house.[180]
Republic of Ireland Ireland: Starting monday 18th of May, the use of cloth face covering is recommend in enclosed public spaces where it's difficult to maintain social distance.[181][182]
Israel Israel: All residents are asked to wear face masks when in public.[183]
Italy Italy: Regions of Lombardy and Tuscany made wearing a face mask compulsory before going out in early April.[184]
Ivory Coast Ivory Coast: From April, 26 masks have become compulsory to enter shopping malls or supermarkets in the Southern suburb of Abidjan, Marcory.[185]
Japan Japan: Masks have been widely used by healthy individuals despite absence of official advice to do so.[186] On 1 March, prime minister Shinzo Abe enacted a policy in Hokkaido instructing manufacturers to sell face masks directly to the government, which would then deliver them to residents.[187]
Kenya Kenya: Wearing a face mask is compulsory since April 4. The government has Kenyans to strictly observe social distancing, which has been proved to one of the most efficient ways of preventing infection risks.[188]
Liberia Liberia: From 21 April, it is now compulsory to wear a face mask or covering in public.[189]
Lithuania Lithuania: Wearing a face mask or any other means of covering one's nose and mouth in public places is compulsory since 10 April 2020.
Luxembourg Luxembourg: From 20 April, wearing a mask is mandatory in places where it is not possible to keep enough distance to others such as supermarkets or on public transport.[190]
Malaysia Malaysia: Masks have been widely used by healthy individuals despite absence of official advice to do so.[191] On 17 March, Malaysia banned exports of medical and surgical masks, to meet local demand.[192] In April, the government was set to distribute 24.62 million masks, four for each household, while advising people to only use them if they have symptoms.[180]
Mexico Mexico: From 17 April, all Mexico City Metro passengers must wear masks while inside stations and on trains, Mayor Claudia Sheinbaum announced on 15 April.[193]
Mongolia Mongolia: Wearing a mask is now mandatory while riding public transportation in Ulaanbaatar. Public officials and news broadcasters had even adopted to wearing masks through press conferences and news broadcasts.[194]
Morocco Morocco: Wearing a face mask is compulsory.[195]
Mozambique Mozambique: The Mozambican government announced on 8 April that wearing face masks is now compulsory on all forms of passenger transport, and wherever groups of people are gathered.[196]
North Macedonia North Macedonia: As of 22 April, citizens of Kumanovo, Tetovo, and Prilep must wear protective masks and gloves outside their homes, at public places, outdoor and indoor areas, markets, and shops announced the government.[197]
Pakistan Pakistan: The Balochistan government on 18 April told citizens to wear face masks when going outside. According to provincial government spokesperson Liaquat Shahwani, citizens have been urged to wear masks or to cover their faces with any cloth in the wake of the COVID-19 outbreak.[198]
Panama Panama: Panama has made it obligatory to wear a face mask whenever going outside, while also recommending the manufacture of a homemade cloth face mask to those who cannot purchase face masks.[199]
Peru Peru: From 7 April, the Peruvian government started distributing free masks after decreeing their mandatory use in the streets to chase away the new coronavirus, said President Martin Vizcarra.[200]
Philippines Philippines: From 2 April, the government required all those living in areas under enhanced community quarantine to wear face masks.[201]
Poland Poland: Since 16 April, covering lips and nose is compulsory before leaving one's house (e.g., by a disposable mask, cloth mask, or scarf).[202]
Russia Russia: Khabarovsk has made the wearing of face masks obligatory to fight the spike in respiratory diseases and prevent the spread of the coronavirus.[203]
Rwanda Rwanda: On 20 April, Cabinet Minister of Health Daniel Ngamije said the latest guidelines require everyone to wear a mask in public, and at home during the lockdown and thereafter.[169]
Scotland Scotland: On 28 April, the First Minister for Scotland Nicola Sturgeon advised the voluntary use of cloth face masks in enclosed spaces such as shops and public transport (but not generally in public), while noting their limitation.[204]
Singapore Singapore: Masks have been widely used by healthy individuals despite initial absence of official advice to do so.[205] General mask-wearing was no longer discouraged from 3 April,[206] and made mandatory outside of one's residence from 14 April.[207]
Spain Spain: Wearing masks has been required since 4 May while on public transportation, which includes taxis, trains and buses. The government is providing masks to the majority of people riding public transportation, regardless of if they have a mask on.[208][209]
Slovakia Slovakia: Forbidden to go out in public without wearing a mask or covering one's nose and mouth.[167][156]
Slovenia Slovenia: From 29 March, wearing a face mask, even one made at home, or equivalents such as scarves that cover the mouth and nose is mandatory along with protective gloves; the decree stipulates that masks and gloves need to be worn in indoor public spaces.[210]
South Africa South Africa: On 10 April, Minister of Health recommended that the general public use cloth face masks when going out in public (in addition to hand-washing and social distancing).[211] After 1 May, covering one's nose and mouth will be mandatory in public (with a cloth mask, scarf, T-shirt, etc.).[212]
South Korea South Korea: Masks have been widely used by healthy individuals despite absence of official advice to do so.[213] The government implemented a policy of centralized procurement and rationing of face masks, purchasing 80 percent of national production since early March.[214]
Sweden Sweden: Sweden's Public Health Agency doubts the effectiveness of face masks, and the agency does not recommend public use of face masks.[215] The government has also warned that wearing them might create a false sense of security.[216]
Taiwan Taiwan: On 21 January, the government announced a temporary ban on the export of face masks.[217] On 6 February, the government instituted a mask rationing system.[218] Taiwan has been producing ten million masks per day since mid-March.[219] On 1 April, passengers on trains and intercity buses were required to wear face masks,[220] unmasked riders facing a fine.[221]
Turkey Turkey: Residents will be required to wear masks at markets, as Turkish president announced.[222]
Ukraine Ukraine: Since 6 April, wearing a face mask is required by the government in public places. In Kyiv, public places were clarified to include parks and streets.[223]
United States United States: On 6 April, the CDC recommended the wearing of non-medical cloth face coverings when in public places.[224][225] Since 17 April, residents of New York, must wear masks in public; New Jersey and Maryland issued similar requirements for their residents.[226]
Uzbekistan Uzbekistan: Officials made protective masks mandatory in all major cities in order to prevent the spread of coronavirus. Officials on 22 March said citizens not wearing masks in public in major cities would be fined $22 for the first offense and $67 for repeat offenses.[227]
Venezuela Venezuela: The government ordered the country’s citizens to wear face masks in public in response to the arrival of the novel coronavirus.[228]
Vietnam Vietnam: Since 16 March, everyone must wear a face mask when going to public places (such as grocery stores, transportation hubs, and public transport).[229]
Zambia Zambia: The government made it mandatory to wear face masks to minimise the spread in the country.[230]
en.wikipedia.org/wiki/Face_masks_during_the_COVID-19_pand...
An eerily quiet Wuhan Airport.as Chinese authorities seek to contain the 2019 Novel Coronavirus (COVID-19). The new virus originally broke out in Wuhan city and is currently spreading worldwide.
Image copyright Flightradar24.com
World Health Organisation:
A domestic Chinese flight passes over an eerily quiet Wuhan Airport as Chinese authorities seek to contain the 2019 Novel Coronavirus (COVID-19). The new virus originally broke out in Wuhan city and is currently spreading worldwide.
Image copyright Flightradar24.com
World Health Organisation:
just watching, and waiting,
outside my sequestered door. As the oldest in the house... for whom the bell tolls... I prefer the plaintive coos of the nesting owls in the neighboring tree.
Once I accepted the inevitability of exposure, I focused on resistance: boosting my immune system and antivirals. I’ll share what I take daily, and if anyone is aware of any reason to *not* take these in the context of coronavirus, please let me know and I’ll update. I have not had a sick day for decades, and perhaps this helped, but remember that my personal journey is not prescriptive and that none of these have been properly studied to reach any conclusions on efficacy, yet:
1) Vitamin D (+ K2 for better absorption): “Studies have indicated that there is a high prevalence of vitamin D deficiency worldwide. Vitamin D deficiency may affect the immune system as vitamin D plays an immunomodulation role, enhancing innate immunity by up-regulating the expression and secretion of antimicrobial peptides, which boosts mucosal defenses. Furthermore, recent meta-analyses have reported a protective effect of vitamin D supplementation on respiratory tract infections” — WHO and an apparently biased site, but some links: Vitamin D Wiki
2) Magical mushroom powder of Shitake + Maitake: “We found significant stimulation of defense reaction. In all cases, the most active was the Maitake-Shiitake combination” — NIH
3) Coconut oil: “Several in vitro, animal, and human studies support the potential of coconut oil, lauric acid and its derivatives as effective and safe agents against a virus like nCoV-2019. Mechanistic studies on other viruses show that at least three mechanisms may be operating. Given the safety and broad availability of virgin coconut oil (VCO), we recommend that VCO be considered as a general prophylactic against viral and microbial infection.” — Ateneo University
4) Zinc, short term use: “In this study we demonstrate that the combination of Zn(2+) and PT at low concentrations (2 µM Zn(2+) and 2 µM PT) inhibits the replication of SARS-coronavirus (SARS-CoV)” — Researchgate And some warnings about prolonged use: Oregon State
5) Oregano oil capsules: “Mexican oregano oil and its main component, carvacrol, are able to inhibit different human and animal viruses in vitro.” — NIH
And then found to be helpful with other viruses, like norovirus and herpes: “This study provides novel findings on the antiviral properties of oregano oil” — sfamjournals
6) Vitamin C: “2019-nCoV infected pneumonia, namely severe acute respiratory infection (SARI) has caused global concern and emergency. We hypothesize that Vitamin C infusion can help improve the prognosis of patients with SARI. Therefore, it is necessary to study the clinical efficacy” — Clinicaltrials
These are all inexpensive on Amazon, but if you want an even stronger placebo effect, find the most expensive version, as that is proven to work better :) ScienceDaily
7) Update: I have added Quercetin. Its impact on Covid-19 has not yet been properly researched, but the basic mechanism could be similar to Chloroquine, and is an over-the-counter supplement even if you don’t have symptoms. Best with Zinc. From molecular simulation studies: "Liu et al. (2020) successfully crystallised the COVID-19 main protease (Mpro), which is a potential drug target. Quercetin... and curcumin [among others] appeared to have the best potential to act as COVID-19 Mpro inhibitors."
8) I also take NMN + TMG and have been discussing possible downstream NAD+ / sirtuin effects on COVID-19 with David Sinclair of Harvard Medical School. As with all of these, nothing is proven; it's just a fascinating hypothesis. The observed age effect on mortality is stark — the younger a person is, across the spectrum, the lower the death rate and hospitalization rate. Looking to NAD+ depletion as we age, and exacerbated by inflammation, perhaps it's ultimately an energy crisis and a loss of NAD + ATP that does us in.
Snips from his recent book Lifespan:
“NAD boosts the activity of all seven sirtuins. And because NAD is used by over 500 different enzymes, without any NAD, we’d be dead in 30 seconds. NAD acts as a fuel for sirtuins. NAD levels decrease with age throughout the body. Human studies with NAD boosters (NMN and NR) are ongoing. So far, there has been no toxicity, not even a hint of it.” (p.134)
Also: "Most antiviral drugs target specific viral proteins. Consequently, they often work for only one virus, and their efficacy can be compromised by the rapid evolution of resistant variants. There is a need for the identification of host proteins with broad-spectrum antiviral functions, which provide effective targets for therapeutic treatments that limit the evolution of viral resistance. Here, we report that sirtuins present such an opportunity for the development of broad-spectrum antiviral treatments, since our findings highlight these enzymes as ancient defense factors that protect against a variety of viral pathogens." — Researchgate
Sinclair added trimethylglycine (TMG) in a recent podcast. He also mentions not to take NMN or NR at night as they interfere with sleep.
H/T Nova Spivack for the corona-relevant links. He is maintaining a more complete list here.
“Ah, distinctly I remember
it was in the bleak December
And each separate dying ember
wrought its ghost upon the floor.
Much I marvelled this ungainly fowl
to hear discourse so plainly,
Though its answer little meaning—
little relevancy bore
For we cannot help agreeing
that no living human being
Ever yet was blessed with seeing
bird above his chamber door
What this grim, ungainly, ghastly, gaunt,
and ominous bird of yore
Meant in croaking ‘Nevermore.’”
— Edgar Allan Poe
The High-speed Marine Transport Co., Ltd.'s passenger and cargo ship MV Hakuou, chartered by Japan Ministry of Defense, is moored at Yokosuka Naval Base, Japan, February 4, 2020, during a disaster relief operation.
At first, the ship was planned to be used as accommodation facility for Japanese people returning from China on charter flights due to Novel Coronavirus (COVID-19) outbreak, but later the plan was changed and the ship was used as accommodation facility for Japan Self-Defense Force's officers dedicated to a life support mission for passengers waiting for the quarantine period until February 19, 2020 on the cruise ship MV Diamond Princess (IMO: 9228198, MMSI: 235103359) where COVID-19 outbreak occured.
Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).[8] The disease was first identified in December 2019 in Wuhan, the capital of China's Hubei province, and has since spread globally, resulting in the ongoing 2019–20 coronavirus pandemic.[9][10] As of 26 April 2020, more than 2.89 million cases have been reported across 185 countries and territories, resulting in more than 203,000 deaths. More than 822,000 people have recovered.[7]
Common symptoms include fever, cough, fatigue, shortness of breath and loss of smell.[5][11][12] While the majority of cases result in mild symptoms, some progress to viral pneumonia, multi-organ failure, or cytokine storm.[13][9][14] More concerning symptoms include difficulty breathing, persistent chest pain, confusion, difficulty waking, and bluish skin.[5] The time from exposure to onset of symptoms is typically around five days but may range from two to fourteen days.[5][15]
The virus is primarily spread between people during close contact,[a] often via small droplets produced by coughing,[b] sneezing, or talking.[6][16][18] The droplets usually fall to the ground or onto surfaces rather than remaining in the air over long distances.[6][19][20] People may also become infected by touching a contaminated surface and then touching their face.[6][16] In experimental settings, the virus may survive on surfaces for up to 72 hours.[21][22][23] It is most contagious during the first three days after the onset of symptoms, although spread may be possible before symptoms appear and in later stages of the disease.[24] The standard method of diagnosis is by real-time reverse transcription polymerase chain reaction (rRT-PCR) from a nasopharyngeal swab.[25] Chest CT imaging may also be helpful for diagnosis in individuals where there is a high suspicion of infection based on symptoms and risk factors; however, guidelines do not recommend using it for routine screening.[26][27]
Recommended measures to prevent infection include frequent hand washing, maintaining physical distance from others (especially from those with symptoms), covering coughs, and keeping unwashed hands away from the face.[28][29] In addition, the use of a face covering is recommended for those who suspect they have the virus and their caregivers.[30][31] Recommendations for face covering use by the general public vary, with some authorities recommending against their use, some recommending their use, and others requiring their use.[32][31][33] Currently, there is not enough evidence for or against the use of masks (medical or other) in healthy individuals in the wider community.[6] Also masks purchased by the public may impact availability for health care providers.
Currently, there is no vaccine or specific antiviral treatment for COVID-19.[6] Management involves the treatment of symptoms, supportive care, isolation, and experimental measures.[34] The World Health Organization (WHO) declared the 2019–20 coronavirus outbreak a Public Health Emergency of International Concern (PHEIC)[35][36] on 30 January 2020 and a pandemic on 11 March 2020.[10] Local transmission of the disease has occurred in most countries across all six WHO regions.[37]
File:En.Wikipedia-VideoWiki-Coronavirus disease 2019.webm
Video summary (script)
Contents
1Signs and symptoms
2Cause
2.1Transmission
2.2Virology
3Pathophysiology
3.1Immunopathology
4Diagnosis
4.1Pathology
5Prevention
6Management
6.1Medications
6.2Protective equipment
6.3Mechanical ventilation
6.4Acute respiratory distress syndrome
6.5Experimental treatment
6.6Information technology
6.7Psychological support
7Prognosis
7.1Reinfection
8History
9Epidemiology
9.1Infection fatality rate
9.2Sex differences
10Society and culture
10.1Name
10.2Misinformation
10.3Protests
11Other animals
12Research
12.1Vaccine
12.2Medications
12.3Anti-cytokine storm
12.4Passive antibodies
13See also
14Notes
15References
16External links
16.1Health agencies
16.2Directories
16.3Medical journals
Signs and symptoms
Symptom[4]Range
Fever83–99%
Cough59–82%
Loss of Appetite40–84%
Fatigue44–70%
Shortness of breath31–40%
Coughing up sputum28–33%
Loss of smell15[38] to 30%[12][39]
Muscle aches and pains11–35%
Fever is the most common symptom, although some older people and those with other health problems experience fever later in the disease.[4][40] In one study, 44% of people had fever when they presented to the hospital, while 89% went on to develop fever at some point during their hospitalization.[4][41]
Other common symptoms include cough, loss of appetite, fatigue, shortness of breath, sputum production, and muscle and joint pains.[4][5][42][43] Symptoms such as nausea, vomiting and diarrhoea have been observed in varying percentages.[44][45][46] Less common symptoms include sneezing, runny nose, or sore throat.[47]
More serious symptoms include difficulty breathing, persistent chest pain or pressure, confusion, difficulty waking, and bluish face or lips. Immediate medical attention is advised if these symptoms are present.[5][48]
In some, the disease may progress to pneumonia, multi-organ failure, and death.[9][14] In those who develop severe symptoms, time from symptom onset to needing mechanical ventilation is typically eight days.[4] Some cases in China initially presented with only chest tightness and palpitations.[49]
Loss of smell was identified as a common symptom of COVID‑19 in March 2020,[12][39] although perhaps not as common as initially reported.[38] A decreased sense of smell and/or disturbances in taste have also been reported.[50] Estimates for loss of smell range from 15%[38] to 30%.[12][39]
As is common with infections, there is a delay between the moment a person is first infected and the time he or she develops symptoms. This is called the incubation period. The incubation period for COVID‑19 is typically five to six days but may range from two to 14 days,[51][52] although 97.5% of people who develop symptoms will do so within 11.5 days of infection.[53]
A minority of cases do not develop noticeable symptoms at any point in time.[54][55] These asymptomatic carriers tend not to get tested, and their role in transmission is not yet fully known.[56][57] However, preliminary evidence suggests they may contribute to the spread of the disease.[58][59] In March 2020, the Korea Centers for Disease Control and Prevention (KCDC) reported that 20% of confirmed cases remained asymptomatic during their hospital stay.[59][60]
A number of neurological symptoms has been reported including seizures, stroke, encephalitis and Guillain-Barre syndrome.[61] Cardiovascular related complications may include heart failure, irregular electrical activity, blood clots, and heart inflammation.[62]
Cause
See also: Severe acute respiratory syndrome coronavirus 2
Transmission
Cough/sneeze droplets visualised in dark background using Tyndall scattering
Respiratory droplets produced when a man is sneezing visualised using Tyndall scattering
File:COVID19 in numbers- R0, the case fatality rate and why we need to flatten the curve.webm
A video discussing the basic reproduction number and case fatality rate in the context of the pandemic
Some details about how the disease is spread are still being determined.[16][18] The WHO and the U.S. Centers for Disease Control and Prevention (CDC) say it is primarily spread during close contact and by small droplets produced when people cough, sneeze or talk;[6][16] with close contact being within approximately 1–2 m (3–7 ft).[6][63] Both sputum and saliva can carry large viral loads.[64] Loud talking releases more droplets than normal talking.[65] A study in Singapore found that an uncovered cough can lead to droplets travelling up to 4.5 metres (15 feet).[66] An article published in March 2020 argued that advice on droplet distance might be based on 1930s research which ignored the effects of warm moist exhaled air surrounding the droplets and that an uncovered cough or sneeze can travel up to 8.2 metres (27 feet).[17]
Respiratory droplets may also be produced while breathing out, including when talking. Though the virus is not generally airborne,[6][67] the National Academy of Sciences has suggested that bioaerosol transmission may be possible.[68] In one study cited, air collectors positioned in the hallway outside of people's rooms yielded samples positive for viral RNA but finding infectious virus has proven elusive.[68] The droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs.[16] Some medical procedures such as intubation and cardiopulmonary resuscitation (CPR) may cause respiratory secretions to be aerosolised and thus result in an airborne spread.[67] Initial studies suggested a doubling time of the number of infected persons of 6–7 days and a basic reproduction number (R0 ) of 2.2–2.7, but a study published on April 7, 2020, calculated a much higher median R0 value of 5.7 in Wuhan.[69]
It may also spread when one touches a contaminated surface, known as fomite transmission, and then touches one's eyes, nose or mouth.[6] While there are concerns it may spread via faeces, this risk is believed to be low.[6][16]
The virus is most contagious when people are symptomatic; though spread is may be possible before symptoms emerge and from those who never develop symptoms.[6][70] A portion of individuals with coronavirus lack symptoms.[71] The European Centre for Disease Prevention and Control (ECDC) says while it is not entirely clear how easily the disease spreads, one person generally infects two or three others.[18]
The virus survives for hours to days on surfaces.[6][18] Specifically, the virus was found to be detectable for one day on cardboard, for up to three days on plastic (polypropylene) and stainless steel (AISI 304), and for up to four hours on 99% copper.[21][23] This, however, varies depending on the humidity and temperature.[72][73] Surfaces may be decontaminated with many solutions (with one minute of exposure to the product achieving a 4 or more log reduction (99.99% reduction)), including 78–95% ethanol (alcohol used in spirits), 70–100% 2-propanol (isopropyl alcohol), the combination of 45% 2-propanol with 30% 1-propanol, 0.21% sodium hypochlorite (bleach), 0.5% hydrogen peroxide, or 0.23–7.5% povidone-iodine. Soap and detergent are also effective if correctly used; soap products degrade the virus' fatty protective layer, deactivating it, as well as freeing them from the skin and other surfaces.[74] Other solutions, such as benzalkonium chloride and chlorhexidine gluconate (a surgical disinfectant), are less effective.[75]
In a Hong Kong study, saliva samples were taken a median of two days after the start of hospitalization. In five of six patients, the first sample showed the highest viral load, and the sixth patient showed the highest viral load on the second day tested.[64]
Virology
Main article: Severe acute respiratory syndrome coronavirus 2
Illustration of SARSr-CoV virion
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel severe acute respiratory syndrome coronavirus, first isolated from three people with pneumonia connected to the cluster of acute respiratory illness cases in Wuhan.[76] All features of the novel SARS-CoV-2 virus occur in related coronaviruses in nature.[77] Outside the human body, the virus is killed by household soap, which bursts its protective bubble.[26]
SARS-CoV-2 is closely related to the original SARS-CoV.[78] It is thought to have a zoonotic origin. Genetic analysis has revealed that the coronavirus genetically clusters with the genus Betacoronavirus, in subgenus Sarbecovirus (lineage B) together with two bat-derived strains. It is 96% identical at the whole genome level to other bat coronavirus samples (BatCov RaTG13).[47] In February 2020, Chinese researchers found that there is only one amino acid difference in the binding domain of the S protein between the coronaviruses from pangolins and those from humans; however, whole-genome comparison to date found that at most 92% of genetic material was shared between pangolin coronavirus and SARS-CoV-2, which is insufficient to prove pangolins to be the intermediate host.[79]
Pathophysiology
The lungs are the organs most affected by COVID‑19 because the virus accesses host cells via the enzyme angiotensin-converting enzyme 2 (ACE2), which is most abundant in type II alveolar cells of the lungs. The virus uses a special surface glycoprotein called a "spike" (peplomer) to connect to ACE2 and enter the host cell.[80] The density of ACE2 in each tissue correlates with the severity of the disease in that tissue and some have suggested that decreasing ACE2 activity might be protective,[81][82] though another view is that increasing ACE2 using angiotensin II receptor blocker medications could be protective and these hypotheses need to be tested.[83] As the alveolar disease progresses, respiratory failure might develop and death may follow.[82]
The virus also affects gastrointestinal organs as ACE2 is abundantly expressed in the glandular cells of gastric, duodenal and rectal epithelium[84] as well as endothelial cells and enterocytes of the small intestine.[85]
ACE2 is present in the brain, and there is growing evidence of neurological manifestations in people with COVID‑19. It is not certain if the virus can directly infect the brain by crossing the barriers that separate the circulation of the brain and the general circulation. Other coronaviruses are able to infect the brain via a synaptic route to the respiratory centre in the medulla, through mechanoreceptors like pulmonary stretch receptors and chemoreceptors (primarily central chemoreceptors) within the lungs.[medical citation needed] It is possible that dysfunction within the respiratory centre further worsens the ARDS seen in COVID‑19 patients. Common neurological presentations include a loss of smell, headaches, nausea, and vomiting. Encephalopathy has been noted to occur in some patients (and confirmed with imaging), with some reports of detection of the virus after cerebrospinal fluid assays although the presence of oligoclonal bands seems to be a common denominator in these patients.[86]
The virus can cause acute myocardial injury and chronic damage to the cardiovascular system.[87] An acute cardiac injury was found in 12% of infected people admitted to the hospital in Wuhan, China,[88] and is more frequent in severe disease.[89] Rates of cardiovascular symptoms are high, owing to the systemic inflammatory response and immune system disorders during disease progression, but acute myocardial injuries may also be related to ACE2 receptors in the heart.[87] ACE2 receptors are highly expressed in the heart and are involved in heart function.[87][90] A high incidence of thrombosis (31%) and venous thromboembolism (25%) have been found in ICU patients with COVID‑19 infections and may be related to poor prognosis.[91][92] Blood vessel dysfunction and clot formation (as suggested by high D-dimer levels) are thought to play a significant role in mortality, incidences of clots leading to pulmonary embolisms, and ischaemic events within the brain have been noted as complications leading to death in patients infected with SARS-CoV-2. Infection appears to set off a chain of vasoconstrictive responses within the body, constriction of blood vessels within the pulmonary circulation has also been posited as a mechanism in which oxygenation decreases alongside with the presentation of viral pneumonia.[93]
Another common cause of death is complications related to the kidneys[93]—SARS-CoV-2 directly infects kidney cells, as confirmed in post-mortem studies. Acute kidney injury is a common complication and cause of death; this is more significant in patients with already compromised kidney function, especially in people with pre-existing chronic conditions such as hypertension and diabetes which specifically cause nephropathy in the long run.[94]
Autopsies of people who died of COVID‑19 have found diffuse alveolar damage (DAD), and lymphocyte-containing inflammatory infiltrates within the lung.[95]
Immunopathology
Although SARS-COV-2 has a tropism for ACE2-expressing epithelial cells of the respiratory tract, patients with severe COVID‑19 have symptoms of systemic hyperinflammation. Clinical laboratory findings of elevated IL-2, IL-7, IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-γ inducible protein 10 (IP-10), monocyte chemoattractant protein 1 (MCP-1), macrophage inflammatory protein 1-α (MIP-1α), and tumour necrosis factor-α (TNF-α) indicative of cytokine release syndrome (CRS) suggest an underlying immunopathology.[96]
Additionally, people with COVID‑19 and acute respiratory distress syndrome (ARDS) have classical serum biomarkers of CRS, including elevated C-reactive protein (CRP), lactate dehydrogenase (LDH), D-dimer, and ferritin.[97]
Systemic inflammation results in vasodilation, allowing inflammatory lymphocytic and monocytic infiltration of the lung and the heart. In particular, pathogenic GM-CSF-secreting T-cells were shown to correlate with the recruitment of inflammatory IL-6-secreting monocytes and severe lung pathology in COVID‑19 patients.[98] Lymphocytic infiltrates have also been reported at autopsy.[95]
Diagnosis
Main article: COVID-19 testing
Demonstration of a nasopharyngeal swab for COVID-19 testing
CDC rRT-PCR test kit for COVID-19[99]
The WHO has published several testing protocols for the disease.[100] The standard method of testing is real-time reverse transcription polymerase chain reaction (rRT-PCR).[101] The test is typically done on respiratory samples obtained by a nasopharyngeal swab; however, a nasal swab or sputum sample may also be used.[25][102] Results are generally available within a few hours to two days.[103][104] Blood tests can be used, but these require two blood samples taken two weeks apart, and the results have little immediate value.[105] Chinese scientists were able to isolate a strain of the coronavirus and publish the genetic sequence so laboratories across the world could independently develop polymerase chain reaction (PCR) tests to detect infection by the virus.[9][106][107] As of 4 April 2020, antibody tests (which may detect active infections and whether a person had been infected in the past) were in development, but not yet widely used.[108][109][110] The Chinese experience with testing has shown the accuracy is only 60 to 70%.[111] The FDA in the United States approved the first point-of-care test on 21 March 2020 for use at the end of that month.[112]
Diagnostic guidelines released by Zhongnan Hospital of Wuhan University suggested methods for detecting infections based upon clinical features and epidemiological risk. These involved identifying people who had at least two of the following symptoms in addition to a history of travel to Wuhan or contact with other infected people: fever, imaging features of pneumonia, normal or reduced white blood cell count, or reduced lymphocyte count.[113]
A study asked hospitalised COVID‑19 patients to cough into a sterile container, thus producing a saliva sample, and detected the virus in eleven of twelve patients using RT-PCR. This technique has the potential of being quicker than a swab and involving less risk to health care workers (collection at home or in the car).[64]
Along with laboratory testing, chest CT scans may be helpful to diagnose COVID-19 in individuals with a high clinical suspicion of infection but are not recommended for routine screening.[26][27] Bilateral multilobar ground-glass opacities with a peripheral, asymmetric, and posterior distribution are common in early infection.[26] Subpleural dominance, crazy paving (lobular septal thickening with variable alveolar filling), and consolidation may appear as the disease progresses.[26][114]
In late 2019, WHO assigned the emergency ICD-10 disease codes U07.1 for deaths from lab-confirmed SARS-CoV-2 infection and U07.2 for deaths from clinically or epidemiologically diagnosed COVID‑19 without lab-confirmed SARS-CoV-2 infection.[115]
Typical CT imaging findings
CT imaging of rapid progression stage
Pathology
Few data are available about microscopic lesions and the pathophysiology of COVID‑19.[116][117] The main pathological findings at autopsy are:
Macroscopy: pleurisy, pericarditis, lung consolidation and pulmonary oedema
Four types of severity of viral pneumonia can be observed:
minor pneumonia: minor serous exudation, minor fibrin exudation
mild pneumonia: pulmonary oedema, pneumocyte hyperplasia, large atypical pneumocytes, interstitial inflammation with lymphocytic infiltration and multinucleated giant cell formation
severe pneumonia: diffuse alveolar damage (DAD) with diffuse alveolar exudates. DAD is the cause of acute respiratory distress syndrome (ARDS) and severe hypoxemia.
healing pneumonia: organisation of exudates in alveolar cavities and pulmonary interstitial fibrosis
plasmocytosis in BAL[118]
Blood: disseminated intravascular coagulation (DIC);[119] leukoerythroblastic reaction[120]
Liver: microvesicular steatosis
Prevention
See also: 2019–20 coronavirus pandemic § Prevention, flatten the curve, and workplace hazard controls for COVID-19
Progressively stronger mitigation efforts to reduce the number of active cases at any given time—known as "flattening the curve"—allows healthcare services to better manage the same volume of patients.[121][122][123] Likewise, progressively greater increases in healthcare capacity—called raising the line—such as by increasing bed count, personnel, and equipment, helps to meet increased demand.[124]
Mitigation attempts that are inadequate in strictness or duration—such as premature relaxation of distancing rules or stay-at-home orders—can allow a resurgence after the initial surge and mitigation.[122][125]
Preventive measures to reduce the chances of infection include staying at home, avoiding crowded places, keeping distance from others, washing hands with soap and water often and for at least 20 seconds, practising good respiratory hygiene, and avoiding touching the eyes, nose, or mouth with unwashed hands.[126][127][128] The CDC recommends covering the mouth and nose with a tissue when coughing or sneezing and recommends using the inside of the elbow if no tissue is available.[126] Proper hand hygiene after any cough or sneeze is encouraged.[126] The CDC has recommended the use of cloth face coverings in public settings where other social distancing measures are difficult to maintain, in part to limit transmission by asymptomatic individuals.[129] The U.S. National Institutes of Health guidelines do not recommend any medication for prevention of COVID‑19, before or after exposure to the SARS-CoV-2 virus, outside of the setting of a clinical trial.[130]
Social distancing strategies aim to reduce contact of infected persons with large groups by closing schools and workplaces, restricting travel, and cancelling large public gatherings.[131] Distancing guidelines also include that people stay at least 6 feet (1.8 m) apart.[132] There is no medication known to be effective at preventing COVID‑19.[133] After the implementation of social distancing and stay-at-home orders, many regions have been able to sustain an effective transmission rate ("Rt") of less than one, meaning the disease is in remission in those areas.[134]
As a vaccine is not expected until 2021 at the earliest,[135] a key part of managing COVID‑19 is trying to decrease the epidemic peak, known as "flattening the curve".[122] This is done by slowing the infection rate to decrease the risk of health services being overwhelmed, allowing for better treatment of current cases, and delaying additional cases until effective treatments or a vaccine become available.[122][125]
According to the WHO, the use of masks is recommended only if a person is coughing or sneezing or when one is taking care of someone with a suspected infection.[136] For the European Centre for Disease Prevention and Control (ECDC) face masks "... could be considered especially when visiting busy closed spaces ..." but "... only as a complementary measure ..."[137] Several countries have recommended that healthy individuals wear face masks or cloth face coverings (like scarves or bandanas) at least in certain public settings, including China,[138] Hong Kong,[139] Spain,[140] Italy (Lombardy region),[141] and the United States.[129]
Those diagnosed with COVID‑19 or who believe they may be infected are advised by the CDC to stay home except to get medical care, call ahead before visiting a healthcare provider, wear a face mask before entering the healthcare provider's office and when in any room or vehicle with another person, cover coughs and sneezes with a tissue, regularly wash hands with soap and water and avoid sharing personal household items.[30][142] The CDC also recommends that individuals wash hands often with soap and water for at least 20 seconds, especially after going to the toilet or when hands are visibly dirty, before eating and after blowing one's nose, coughing or sneezing. It further recommends using an alcohol-based hand sanitiser with at least 60% alcohol, but only when soap and water are not readily available.[126]
For areas where commercial hand sanitisers are not readily available, the WHO provides two formulations for local production. In these formulations, the antimicrobial activity arises from ethanol or isopropanol. Hydrogen peroxide is used to help eliminate bacterial spores in the alcohol; it is "not an active substance for hand antisepsis". Glycerol is added as a humectant.[143]
Prevention efforts are multiplicative, with effects far beyond that of a single spread. Each avoided case leads to more avoided cases down the line, which in turn can stop the outbreak in its tracks.
File:COVID19 W ENG.ogv
Handwashing instructions
Management
People are managed with supportive care, which may include fluid therapy, oxygen support, and supporting other affected vital organs.[144][145][146] The CDC recommends that those who suspect they carry the virus wear a simple face mask.[30] Extracorporeal membrane oxygenation (ECMO) has been used to address the issue of respiratory failure, but its benefits are still under consideration.[41][147] Personal hygiene and a healthy lifestyle and diet have been recommended to improve immunity.[148] Supportive treatments may be useful in those with mild symptoms at the early stage of infection.[149]
The WHO, the Chinese National Health Commission, and the United States' National Institutes of Health have published recommendations for taking care of people who are hospitalised with COVID‑19.[130][150][151] Intensivists and pulmonologists in the U.S. have compiled treatment recommendations from various agencies into a free resource, the IBCC.[152][153]
Medications
See also: Coronavirus disease 2019 § Research
As of April 2020, there is no specific treatment for COVID‑19.[6][133] Research is, however, ongoing. For symptoms, some medical professionals recommend paracetamol (acetaminophen) over ibuprofen for first-line use.[154][155][156] The WHO and NIH do not oppose the use of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen for symptoms,[130][157] and the FDA says currently there is no evidence that NSAIDs worsen COVID‑19 symptoms.[158]
While theoretical concerns have been raised about ACE inhibitors and angiotensin receptor blockers, as of 19 March 2020, these are not sufficient to justify stopping these medications.[130][159][160][161] Steroids, such as methylprednisolone, are not recommended unless the disease is complicated by acute respiratory distress syndrome.[162][163]
Medications to prevent blood clotting have been suggested for treatment,[91] and anticoagulant therapy with low molecular weight heparin appears to be associated with better outcomes in severe COVID‐19 showing signs of coagulopathy (elevated D-dimer).[164]
Protective equipment
See also: COVID-19 related shortages
The CDC recommends four steps to putting on personal protective equipment (PPE).[165]
Precautions must be taken to minimise the risk of virus transmission, especially in healthcare settings when performing procedures that can generate aerosols, such as intubation or hand ventilation.[166] For healthcare professionals caring for people with COVID‑19, the CDC recommends placing the person in an Airborne Infection Isolation Room (AIIR) in addition to using standard precautions, contact precautions, and airborne precautions.[167]
The CDC outlines the guidelines for the use of personal protective equipment (PPE) during the pandemic. The recommended gear is a PPE gown, respirator or facemask, eye protection, and medical gloves.[168][169]
When available, respirators (instead of facemasks) are preferred.[170] N95 respirators are approved for industrial settings but the FDA has authorised the masks for use under an Emergency Use Authorisation (EUA). They are designed to protect from airborne particles like dust but effectiveness against a specific biological agent is not guaranteed for off-label uses.[171] When masks are not available, the CDC recommends using face shields or, as a last resort, homemade masks.[172]
Mechanical ventilation
Most cases of COVID‑19 are not severe enough to require mechanical ventilation or alternatives, but a percentage of cases are.[173][174] The type of respiratory support for individuals with COVID‑19 related respiratory failure is being actively studied for people in the hospital, with some evidence that intubation can be avoided with a high flow nasal cannula or bi-level positive airway pressure.[175] Whether either of these two leads to the same benefit for people who are critically ill is not known.[176] Some doctors prefer staying with invasive mechanical ventilation when available because this technique limits the spread of aerosol particles compared to a high flow nasal cannula.[173]
Severe cases are most common in older adults (those older than 60 years,[173] and especially those older than 80 years).[177] Many developed countries do not have enough hospital beds per capita, which limits a health system's capacity to handle a sudden spike in the number of COVID‑19 cases severe enough to require hospitalisation.[178] This limited capacity is a significant driver behind calls to flatten the curve.[178] One study in China found 5% were admitted to intensive care units, 2.3% needed mechanical support of ventilation, and 1.4% died.[41] In China, approximately 30% of people in hospital with COVID‑19 are eventually admitted to ICU.[4]
Acute respiratory distress syndrome
Main article: Acute respiratory distress syndrome
Mechanical ventilation becomes more complex as acute respiratory distress syndrome (ARDS) develops in COVID‑19 and oxygenation becomes increasingly difficult.[179] Ventilators capable of pressure control modes and high PEEP[180] are needed to maximise oxygen delivery while minimising the risk of ventilator-associated lung injury and pneumothorax.[181] High PEEP may not be available on older ventilators.
Options for ARDS[179]
TherapyRecommendations
High-flow nasal oxygenFor SpO2 <93%. May prevent the need for intubation and ventilation
Tidal volume6mL per kg and can be reduced to 4mL/kg
Plateau airway pressureKeep below 30 cmH2O if possible (high respiratory rate (35 per minute) may be required)
Positive end-expiratory pressureModerate to high levels
Prone positioningFor worsening oxygenation
Fluid managementGoal is a negative balance of 0.5–1.0L per day
AntibioticsFor secondary bacterial infections
GlucocorticoidsNot recommended
Experimental treatment
See also: § Research
Research into potential treatments started in January 2020,[182] and several antiviral drugs are in clinical trials.[183][184] Remdesivir appears to be the most promising.[133] Although new medications may take until 2021 to develop,[185] several of the medications being tested are already approved for other uses or are already in advanced testing.[186] Antiviral medication may be tried in people with severe disease.[144] The WHO recommended volunteers take part in trials of the effectiveness and safety of potential treatments.[187]
The FDA has granted temporary authorisation to convalescent plasma as an experimental treatment in cases where the person's life is seriously or immediately threatened. It has not undergone the clinical studies needed to show it is safe and effective for the disease.[188][189][190]
Information technology
See also: Contact tracing and Government by algorithm
In February 2020, China launched a mobile app to deal with the disease outbreak.[191] Users are asked to enter their name and ID number. The app can detect 'close contact' using surveillance data and therefore a potential risk of infection. Every user can also check the status of three other users. If a potential risk is detected, the app not only recommends self-quarantine, it also alerts local health officials.[192]
Big data analytics on cellphone data, facial recognition technology, mobile phone tracking, and artificial intelligence are used to track infected people and people whom they contacted in South Korea, Taiwan, and Singapore.[193][194] In March 2020, the Israeli government enabled security agencies to track mobile phone data of people supposed to have coronavirus. The measure was taken to enforce quarantine and protect those who may come into contact with infected citizens.[195] Also in March 2020, Deutsche Telekom shared aggregated phone location data with the German federal government agency, Robert Koch Institute, to research and prevent the spread of the virus.[196] Russia deployed facial recognition technology to detect quarantine breakers.[197] Italian regional health commissioner Giulio Gallera said he has been informed by mobile phone operators that "40% of people are continuing to move around anyway".[198] German government conducted a 48 hours weekend hackathon with more than 42.000 participants.[199][200] Two million people in the UK used an app developed in March 2020 by King's College London and Zoe to track people with COVID‑19 symptoms.[201] Also, the president of Estonia, Kersti Kaljulaid, made a global call for creative solutions against the spread of coronavirus.[202]
Psychological support
See also: Mental health during the 2019–20 coronavirus pandemic
Individuals may experience distress from quarantine, travel restrictions, side effects of treatment, or fear of the infection itself. To address these concerns, the National Health Commission of China published a national guideline for psychological crisis intervention on 27 January 2020.[203][204]
The Lancet published a 14-page call for action focusing on the UK and stated conditions were such that a range of mental health issues was likely to become more common. BBC quoted Rory O'Connor in saying, "Increased social isolation, loneliness, health anxiety, stress and an economic downturn are a perfect storm to harm people's mental health and wellbeing."[205][206]
Prognosis
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The severity of diagnosed cases in China
The severity of diagnosed COVID-19 cases in China[207]
Case fatality rates for COVID-19 by age by country.
Case fatality rates by age group:
China, as of 11 February 2020[208]
South Korea, as of 15 April 2020[209]
Spain, as of 24 April 2020[210]
Italy, as of 23 April 2020[211]
Case fatality rate depending on other health problems
Case fatality rate in China depending on other health problems. Data through 11 February 2020.[208]
Case fatality rate by country and number of cases
The number of deaths vs total cases by country and approximate case fatality rate[212]
The severity of COVID‑19 varies. The disease may take a mild course with few or no symptoms, resembling other common upper respiratory diseases such as the common cold. Mild cases typically recover within two weeks, while those with severe or critical diseases may take three to six weeks to recover. Among those who have died, the time from symptom onset to death has ranged from two to eight weeks.[47]
Children make up a small proportion of reported cases, with about 1% of cases being under 10 years, and 4% aged 10-19 years.[22] They are likely to have milder symptoms and a lower chance of severe disease than adults; in those younger than 50 years, the risk of death is less than 0.5%, while in those older than 70 it is more than 8%.[213][214][215] Pregnant women may be at higher risk for severe infection with COVID-19 based on data from other similar viruses, like SARS and MERS, but data for COVID-19 is lacking.[216][217] In China, children acquired infections mainly through close contact with their parents or other family members who lived in Wuhan or had traveled there.[213]
In some people, COVID‑19 may affect the lungs causing pneumonia. In those most severely affected, COVID-19 may rapidly progress to acute respiratory distress syndrome (ARDS) causing respiratory failure, septic shock, or multi-organ failure.[218][219] Complications associated with COVID‑19 include sepsis, abnormal clotting, and damage to the heart, kidneys, and liver. Clotting abnormalities, specifically an increase in prothrombin time, have been described in 6% of those admitted to hospital with COVID-19, while abnormal kidney function is seen in 4% of this group.[220] Approximately 20-30% of people who present with COVID‑19 demonstrate elevated liver enzymes (transaminases).[133] Liver injury as shown by blood markers of liver damage is frequently seen in severe cases.[221]
Some studies have found that the neutrophil to lymphocyte ratio (NLR) may be helpful in early screening for severe illness.[222]
Most of those who die of COVID‑19 have pre-existing (underlying) conditions, including hypertension, diabetes mellitus, and cardiovascular disease.[223] The Istituto Superiore di Sanità reported that out of 8.8% of deaths where medical charts were available for review, 97.2% of sampled patients had at least one comorbidity with the average patient having 2.7 diseases.[224] According to the same report, the median time between the onset of symptoms and death was ten days, with five being spent hospitalised. However, patients transferred to an ICU had a median time of seven days between hospitalisation and death.[224] In a study of early cases, the median time from exhibiting initial symptoms to death was 14 days, with a full range of six to 41 days.[225] In a study by the National Health Commission (NHC) of China, men had a death rate of 2.8% while women had a death rate of 1.7%.[226] Histopathological examinations of post-mortem lung samples show diffuse alveolar damage with cellular fibromyxoid exudates in both lungs. Viral cytopathic changes were observed in the pneumocytes. The lung picture resembled acute respiratory distress syndrome (ARDS).[47] In 11.8% of the deaths reported by the National Health Commission of China, heart damage was noted by elevated levels of troponin or cardiac arrest.[49] According to March data from the United States, 89% of those hospitalised had preexisting conditions.[227]
The availability of medical resources and the socioeconomics of a region may also affect mortality.[228] Estimates of the mortality from the condition vary because of those regional differences,[229] but also because of methodological difficulties. The under-counting of mild cases can cause the mortality rate to be overestimated.[230] However, the fact that deaths are the result of cases contracted in the past can mean the current mortality rate is underestimated.[231][232] Smokers were 1.4 times more likely to have severe symptoms of COVID‑19 and approximately 2.4 times more likely to require intensive care or die compared to non-smokers.[233]
Concerns have been raised about long-term sequelae of the disease. The Hong Kong Hospital Authority found a drop of 20% to 30% in lung capacity in some people who recovered from the disease, and lung scans suggested organ damage.[234] This may also lead to post-intensive care syndrome following recovery.[235]
Case fatality rates (%) by age and country
Age0–910–1920–2930–3940–4950–5960–6970–7980-8990+
China as of 11 February[208]0.00.20.20.20.41.33.68.014.8
Denmark as of 25 April[236]0.24.515.524.940.7
Italy as of 23 April[211]0.20.00.10.40.92.610.024.930.826.1
Netherlands as of 17 April[237]0.00.30.10.20.51.57.623.230.029.3
Portugal as of 24 April[238]0.00.00.00.00.30.62.88.516.5
S. Korea as of 15 April[209]0.00.00.00.10.20.72.59.722.2
Spain as of 24 April[210]0.30.40.30.30.61.34.413.220.320.1
Switzerland as of 25 April[239]0.90.00.00.10.00.52.710.124.0
Case fatality rates (%) by age in the United States
Age0–1920–4445–5455–6465–7475–8485+
United States as of 16 March[240]0.00.1–0.20.5–0.81.4–2.62.7–4.94.3–10.510.4–27.3
Note: The lower bound includes all cases. The upper bound excludes cases that were missing data.
Estimate of infection fatality rates and probability of severe disease course (%) by age based on cases from China[241]
0–910–1920–2930–3940–4950–5960–6970–7980+
Severe disease0.0
(0.0–0.0)0.04
(0.02–0.08)1.0
(0.62–2.1)3.4
(2.0–7.0)4.3
(2.5–8.7)8.2
(4.9–17)11
(7.0–24)17
(9.9–34)18
(11–38)
Death0.0016
(0.00016–0.025)0.0070
(0.0015–0.050)0.031
(0.014–0.092)0.084
(0.041–0.19)0.16
(0.076–0.32)0.60
(0.34–1.3)1.9
(1.1–3.9)4.3
(2.5–8.4)7.8
(3.8–13)
Total infection fatality rate is estimated to be 0.66% (0.39–1.3). Infection fatality rate is fatality per all infected individuals, regardless of whether they were diagnosed or had any symptoms. Numbers in parentheses are 95% credible intervals for the estimates.
Reinfection
As of March 2020, it was unknown if past infection provides effective and long-term immunity in people who recover from the disease.[242] Immunity is seen as likely, based on the behaviour of other coronaviruses,[243] but cases in which recovery from COVID‑19 have been followed by positive tests for coronavirus at a later date have been reported.[244][245][246][247] These cases are believed to be worsening of a lingering infection rather than re-infection.[247]
History
Main article: Timeline of the 2019–20 coronavirus pandemic
The virus is thought to be natural and has an animal origin,[77] through spillover infection.[248] The actual origin is unknown, but by December 2019 the spread of infection was almost entirely driven by human-to-human transmission.[208][249] A study of the first 41 cases of confirmed COVID‑19, published in January 2020 in The Lancet, revealed the earliest date of onset of symptoms as 1 December 2019.[250][251][252] Official publications from the WHO reported the earliest onset of symptoms as 8 December 2019.[253] Human-to-human transmission was confirmed by the WHO and Chinese authorities by 20 January 2020.[254][255]
Epidemiology
Main article: 2019–20 coronavirus pandemic
Several measures are commonly used to quantify mortality.[256] These numbers vary by region and over time and are influenced by the volume of testing, healthcare system quality, treatment options, time since the initial outbreak, and population characteristics such as age, sex, and overall health.[257]
The death-to-case ratio reflects the number of deaths divided by the number of diagnosed cases within a given time interval. Based on Johns Hopkins University statistics, the global death-to-case ratio is 7.0% (203,044/2,899,830) as of 26 April 2020.[7] The number varies by region.[258]
Other measures include the case fatality rate (CFR), which reflects the percent of diagnosed individuals who die from a disease, and the infection fatality rate (IFR), which reflects the percent of infected individuals (diagnosed and undiagnosed) who die from a disease. These statistics are not time-bound and follow a specific population from infection through case resolution. Many academics have attempted to calculate these numbers for specific populations.[259]
Total confirmed cases over time
Total deaths over time
Total confirmed cases of COVID‑19 per million people, 10 April 2020[260]
Total confirmed deaths due to COVID‑19 per million people, 10 April 2020[261]
Infection fatality rate
Our World in Data states that as of March 25, 2020, the infection fatality rate (IFR) cannot be accurately calculated.[262] In February, the World Health Organization estimated the IFR at 0.94%, with a confidence interval between 0.37 percent to 2.9 percent.[263] The University of Oxford Centre for Evidence-Based Medicine (CEBM) estimated a global CFR of 0.72 percent and IFR of 0.1 percent to 0.36 percent.[264] According to CEBM, random antibody testing in Germany suggested an IFR of 0.37 percent there.[264] Firm lower limits to local infection fatality rates were established, such as in Bergamo province, where 0.57% of the population has died, leading to a minimum IFR of 0.57% in the province. This population fatality rate (PFR) minimum increases as more people get infected and run through their disease.[265][266] Similarly, as of April 22 in the New York City area, there were 15,411 deaths confirmed from COVID-19, and 19,200 excess deaths.[267] Very recently, the first results of antibody testing have come in, but there are no valid scientific reports based on them available yet. A Bloomberg Opinion piece provides a survey.[268][269]
Sex differences
Main article: Gendered impact of the 2019–20 coronavirus pandemic
The impact of the pandemic and its mortality rate are different for men and women.[270] Mortality is higher in men in studies conducted in China and Italy.[271][272][273] The highest risk for men is in their 50s, with the gap between men and women closing only at 90.[273] In China, the death rate was 2.8 percent for men and 1.7 percent for women.[273] The exact reasons for this sex-difference are not known, but genetic and behavioural factors could be a reason.[270] Sex-based immunological differences, a lower prevalence of smoking in women, and men developing co-morbid conditions such as hypertension at a younger age than women could have contributed to the higher mortality in men.[273] In Europe, of those infected with COVID‑19, 57% were men; of those infected with COVID‑19 who also died, 72% were men.[274] As of April 2020, the U.S. government is not tracking sex-related data of COVID‑19 infections.[275] Research has shown that viral illnesses like Ebola, HIV, influenza, and SARS affect men and women differently.[275] A higher percentage of health workers, particularly nurses, are women, and they have a higher chance of being exposed to the virus.[276] School closures, lockdowns, and reduced access to healthcare following the 2019–20 coronavirus pandemic may differentially affect the genders and possibly exaggerate existing gender disparity.[270][277]
Society and culture
Name
During the initial outbreak in Wuhan, China, the virus and disease were commonly referred to as "coronavirus" and "Wuhan coronavirus",[278][279][280] with the disease sometimes called "Wuhan pneumonia".[281][282] In the past, many diseases have been named after geographical locations, such as the Spanish flu,[283] Middle East Respiratory Syndrome, and Zika virus.[284]
In January 2020, the World Health Organisation recommended 2019-nCov[285] and 2019-nCoV acute respiratory disease[286] as interim names for the virus and disease per 2015 guidance and international guidelines against using geographical locations (e.g. Wuhan, China), animal species or groups of people in disease and virus names to prevent social stigma.[287][288][289]
The official names COVID‑19 and SARS-CoV-2 were issued by the WHO on 11 February 2020.[290] WHO chief Tedros Adhanom Ghebreyesus explained: CO for corona, VI for virus, D for disease and 19 for when the outbreak was first identified (31 December 2019).[291] The WHO additionally uses "the COVID‑19 virus" and "the virus responsible for COVID‑19" in public communications.[290] Both the disease and virus are commonly referred to as "coronavirus" in the media and public discourse.
Misinformation
Main article: Misinformation related to the 2019–20 coronavirus pandemic
After the initial outbreak of COVID‑19, conspiracy theories, misinformation, and disinformation emerged regarding the origin, scale, prevention, treatment, and other aspects of the disease and rapidly spread online.[292][293][294][295]
Protests
Beginning April 17, 2020, news media began reporting on a wave of demonstrations protesting against state-mandated quarantine restrictions in in Michigan, Ohio, and Kentucky.[296][297]
Other animals
Humans appear to be capable of spreading the virus to some other animals. A domestic cat in Liège, Belgium, tested positive after it started showing symptoms (diarrhoea, vomiting, shortness of breath) a week later than its owner, who was also positive.[298] Tigers at the Bronx Zoo in New York, United States, tested positive for the virus and showed symptoms of COVID‑19, including a dry cough and loss of appetite.[299]
A study on domesticated animals inoculated with the virus found that cats and ferrets appear to be "highly susceptible" to the disease, while dogs appear to be less susceptible, with lower levels of viral replication. The study failed to find evidence of viral replication in pigs, ducks, and chickens.[300]
Research
Main article: COVID-19 drug development
No medication or vaccine is approved to treat the disease.[186] International research on vaccines and medicines in COVID‑19 is underway by government organisations, academic groups, and industry researchers.[301][302] In March, the World Health Organisation initiated the "SOLIDARITY Trial" to assess the treatment effects of four existing antiviral compounds with the most promise of efficacy.[303]
Vaccine
Main article: COVID-19 vaccine
There is no available vaccine, but various agencies are actively developing vaccine candidates. Previous work on SARS-CoV is being used because both SARS-CoV and SARS-CoV-2 use the ACE2 receptor to enter human cells.[304] Three vaccination strategies are being investigated. First, researchers aim to build a whole virus vaccine. The use of such a virus, be it inactive or dead, aims to elicit a prompt immune response of the human body to a new infection with COVID‑19. A second strategy, subunit vaccines, aims to create a vaccine that sensitises the immune system to certain subunits of the virus. In the case of SARS-CoV-2, such research focuses on the S-spike protein that helps the virus intrude the ACE2 enzyme receptor. A third strategy is that of the nucleic acid vaccines (DNA or RNA vaccines, a novel technique for creating a vaccination). Experimental vaccines from any of these strategies would have to be tested for safety and efficacy.[305]
On 16 March 2020, the first clinical trial of a vaccine started with four volunteers in Seattle, United States. The vaccine contains a harmless genetic code copied from the virus that causes the disease.[306]
Antibody-dependent enhancement has been suggested as a potential challenge for vaccine development for SARS-COV-2, but this is controversial.[307]
Medications
Main article: COVID-19 drug repurposing research
At least 29 phase II–IV efficacy trials in COVID‑19 were concluded in March 2020 or scheduled to provide results in April from hospitals in China.[308][309] There are more than 300 active clinical trials underway as of April 2020.[133] Seven trials were evaluating already approved treatments, including four studies on hydroxychloroquine or chloroquine.[309] Repurposed antiviral drugs make up most of the Chinese research, with nine phase III trials on remdesivir across several countries due to report by the end of April.[308][309] Other candidates in trials include vasodilators, corticosteroids, immune therapies, lipoic acid, bevacizumab, and recombinant angiotensin-converting enzyme 2.[309]
The COVID‑19 Clinical Research Coalition has goals to 1) facilitate rapid reviews of clinical trial proposals by ethics committees and national regulatory agencies, 2) fast-track approvals for the candidate therapeutic compounds, 3) ensure standardised and rapid analysis of emerging efficacy and safety data and 4) facilitate sharing of clinical trial outcomes before publication.[310][311]
Several existing medications are being evaluated for the treatment of COVID‑19,[186] including remdesivir, chloroquine, hydroxychloroquine, lopinavir/ritonavir, and lopinavir/ritonavir combined with interferon beta.[303][312] There is tentative evidence for efficacy by remdesivir, as of March 2020.[313][314] Clinical improvement was observed in patients treated with compassionate-use remdesivir.[315] Remdesivir inhibits SARS-CoV-2 in vitro.[316] Phase III clinical trials are underway in the U.S., China, and Italy.[186][308][317]
In 2020, a trial found that lopinavir/ritonavir was ineffective in the treatment of severe illness.[318] Nitazoxanide has been recommended for further in vivo study after demonstrating low concentration inhibition of SARS-CoV-2.[316]
There are mixed results as of 3 April 2020 as to the effectiveness of hydroxychloroquine as a treatment for COVID‑19, with some studies showing little or no improvement.[319][320] The studies of chloroquine and hydroxychloroquine with or without azithromycin have major limitations that have prevented the medical community from embracing these therapies without further study.[133]
Oseltamivir does not inhibit SARS-CoV-2 in vitro and has no known role in COVID‑19 treatment.[133]
Anti-cytokine storm
Cytokine release syndrome (CRS) can be a complication in the later stages of severe COVID‑19. There is preliminary evidence that hydroxychloroquine may have anti-cytokine storm properties.[321]
Tocilizumab has been included in treatment guidelines by China's National Health Commission after a small study was completed.[322][323] It is undergoing a phase 2 non-randomised trial at the national level in Italy after showing positive results in people with severe disease.[324][325] Combined with a serum ferritin blood test to identify cytokine storms, it is meant to counter such developments, which are thought to be the cause of death in some affected people.[326][327][328] The interleukin-6 receptor antagonist was approved by the FDA to undergo a phase III clinical trial assessing the medication's impact on COVID‑19 based on retrospective case studies for the treatment of steroid-refractory cytokine release syndrome induced by a different cause, CAR T cell therapy, in 2017.[329] To date, there is no randomised, controlled evidence that tocilizumab is an efficacious treatment for CRS. Prophylactic tocilizumab has been shown to increase serum IL-6 levels by saturating the IL-6R, driving IL-6 across the blood-brain barrier, and exacerbating neurotoxicity while having no impact on the incidence of CRS.[330]
Lenzilumab, an anti-GM-CSF monoclonal antibody, is protective in murine models for CAR T cell-induced CRS and neurotoxicity and is a viable therapeutic option due to the observed increase of pathogenic GM-CSF secreting T-cells in hospitalised patients with COVID‑19.[331]
The Feinstein Institute of Northwell Health announced in March a study on "a human antibody that may prevent the activity" of IL-6.[332]
Passive antibodies
Transferring purified and concentrated antibodies produced by the immune systems of those who have recovered from COVID‑19 to people who need them is being investigated as a non-vaccine method of passive immunisation.[333] This strategy was tried for SARS with inconclusive results.[333] Viral neutralisation is the anticipated mechanism of action by which passive antibody therapy can mediate defence against SARS-CoV-2. Other mechanisms, however, such as antibody-dependent cellular cytotoxicity and/or phagocytosis, may be possible.[333] Other forms of passive antibody therapy, for example, using manufactured monoclonal antibodies, are in development.[333] Production of convalescent serum, which consists of the liquid portion of the blood from recovered patients and contains antibodies specific to this virus, could be increased for quicker deployment.[334]
Do not wear masks that: Have exhalation valves or vents which allow virus particles to escape.
#CDCGuideToMasks
www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/ab...
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This article is about the group of viruses. For the disease involved in the 2019–20 coronavirus pandemic, see Coronavirus disease 2019. For the virus that causes this disease, see Severe acute respiratory syndrome coronavirus 2.
Orthocoronavirinae
Coronaviruses 004 lores.jpg
Transmission electron micrograph (TEM) of avian infectious bronchitis virus
SARS-CoV-2 without background.png
Illustration of the morphology of coronaviruses; the club-shaped viral spike peplomers, colored red, create the look of a corona surrounding the virion when observed with an electron microscope.
Virus classification e
(unranked):Virus
Realm:Riboviria
Phylum:incertae sedis
Order:Nidovirales
Family:Coronaviridae
Subfamily:Orthocoronavirinae
Genera[1]
Alphacoronavirus
Betacoronavirus
Gammacoronavirus
Deltacoronavirus
Synonyms[2][3][4]
Coronavirinae
Coronaviruses are a group of related viruses that cause diseases in mammals and birds. In humans, coronaviruses cause respiratory tract infections that can range from mild to lethal. Mild illnesses include some cases of the common cold (which has other possible causes, predominantly rhinoviruses), while more lethal varieties can cause SARS, MERS, and COVID-19. Symptoms in other species vary: in chickens, they cause an upper respiratory tract disease, while in cows and pigs they cause diarrhea. There are yet to be vaccines or antiviral drugs to prevent or treat human coronavirus infections.
Coronaviruses constitute the subfamily Orthocoronavirinae, in the family Coronaviridae, order Nidovirales, and realm Riboviria.[5][6] They are enveloped viruses with a positive-sense single-stranded RNA genome and a nucleocapsid of helical symmetry. The genome size of coronaviruses ranges from approximately 26 to 32 kilobases, one of the largest among RNA viruses.[7] They have characteristic club-shaped spikes that project from their surface, which in electron micrographs create an image reminiscent of the solar corona from which their name derives.[8]
Contents
1Discovery
2Etymology
3Morphology
4Genome
5Life cycle
5.1Entry
5.2Replication
5.3Release
6Transmission
7Taxonomy
8Evolution
9Human coronaviruses
10Outbreaks of coronavirus diseases
10.1Severe acute respiratory syndrome (SARS)
10.2Middle East respiratory syndrome (MERS)
10.3Coronavirus disease 2019 (COVID-19)
11Other animals
11.1Diseases caused
11.2Domestic animals
12Genomic cis-acting elements
13Genome packaging
14See also
15References
16Further reading
Discovery
Coronaviruses were first discovered in the 1930s when an acute respiratory infection of domesticated chickens was shown to be caused by infectious bronchitis virus (IBV). In the 1940s, two more animal coronaviruses, mouse hepatitis virus (MHV) and transmissible gastroenteritis virus (TGEV), were isolated.[9]
Human coronaviruses were discovered in the 1960s.[10] The earliest ones studied were from human patients with the common cold, which were later named human coronavirus 229E and human coronavirus OC43.[11] Other human coronaviruses have since been identified, including SARS-CoV in 2003, HCoV NL63 in 2004, HKU1 in 2005, MERS-CoV in 2012, and SARS-CoV-2 in 2019. Most of these have involved serious respiratory tract infections.
Etymology
The name "coronavirus" is derived from Latin corona, meaning "crown" or "wreath", itself a borrowing from Greek κορώνη korṓnē, "garland, wreath". The name refers to the characteristic appearance of virions (the infective form of the virus) by electron microscopy, which have a fringe of large, bulbous surface projections creating an image reminiscent of a crown or of a solar corona. This morphology is created by the viral spike peplomers, which are proteins on the surface of the virus.[8][12]
Morphology
Cross-sectional model of a coronavirus
Cross-sectional model of a coronavirus
Coronaviruses are large pleomorphic spherical particles with bulbous surface projections.[13] The average diameter of the virus particles is around 120 nm (.12 μm). The diameter of the envelope is ~80 nm (.08 μm) and the spikes are ~20 nm (.02 μm) long. The envelope of the virus in electron micrographs appears as a distinct pair of electron dense shells.[14][15]
The viral envelope consists of a lipid bilayer where the membrane (M), envelope (E) and spike (S) structural proteins are anchored.[16] A subset of coronaviruses (specifically the members of betacoronavirus subgroup A) also have a shorter spike-like surface protein called hemagglutinin esterase (HE).[5]
Inside the envelope, there is the nucleocapsid, which is formed from multiple copies of the nucleocapsid (N) protein, which are bound to the positive-sense single-stranded RNA genome in a continuous beads-on-a-string type conformation.[15][17] The lipid bilayer envelope, membrane proteins, and nucleocapsid protect the virus when it is outside the host cell.[18]
Genome
See also: Severe acute respiratory syndrome-related coronavirus § Genome
Schematic representation of the genome organization and functional domains of S protein for SARS-CoV and MERS-CoV
Coronaviruses contain a positive-sense, single-stranded RNA genome. The genome size for coronaviruses ranges from 26.4 to 31.7 kilobases.[7] The genome size is one of the largest among RNA viruses. The genome has a 5′ methylated cap and a 3′ polyadenylated tail.[15]
The genome organization for a coronavirus is 5′-leader-UTR-replicase/transcriptase-spike (S)-envelope (E)-membrane (M)-nucleocapsid (N)-3′UTR-poly (A) tail. The open reading frames 1a and 1b, which occupy the first two-thirds of the genome, encode the replicase/transcriptase polyprotein. The replicase/transcriptase polyprotein self cleaves to form nonstructural proteins.[15]
The later reading frames encode the four major structural proteins: spike, envelope, membrane, and nucleocapsid.[19] Interspersed between these reading frames are the reading frames for the accessory proteins. The number of accessory proteins and their function is unique depending on the specific coronavirus.[15]
Life cycle
Entry
The life cycle of a coronavirus
Infection begins when the viral spike (S) glycoprotein attaches to its complementary host cell receptor. After attachment, a protease of the host cell cleaves and activates the receptor-attached spike protein. Depending on the host cell protease available, cleavage and activation allows the virus to enter the host cell by endocytosis or direct fusion of the viral envelop with the host membrane.[20]
On entry into the host cell, the virus particle is uncoated, and its genome enters the cell cytoplasm.[15] The coronavirus RNA genome has a 5′ methylated cap and a 3′ polyadenylated tail, which allows the RNA to attach to the host cell's ribosome for translation.[15] The host ribosome translates the initial overlapping open reading frame of the virus genome and forms a long polyprotein. The polyprotein has its own proteases which cleave the polyprotein into multiple nonstructural proteins.[15]
Replication
A number of the nonstructural proteins coalesce to form a multi-protein replicase-transcriptase complex (RTC). The main replicase-transcriptase protein is the RNA-dependent RNA polymerase (RdRp). It is directly involved in the replication and transcription of RNA from an RNA strand. The other nonstructural proteins in the complex assist in the replication and transcription process. The exoribonuclease nonstructural protein, for instance, provides extra fidelity to replication by providing a proofreading function which the RNA-dependent RNA polymerase lacks.[21]
One of the main functions of the complex is to replicate the viral genome. RdRp directly mediates the synthesis of negative-sense genomic RNA from the positive-sense genomic RNA. This is followed by the replication of positive-sense genomic RNA from the negative-sense genomic RNA.[15] The other important function of the complex is to transcribe the viral genome. RdRp directly mediates the synthesis of negative-sense subgenomic RNA molecules from the positive-sense genomic RNA. This is followed by the transcription of these negative-sense subgenomic RNA molecules to their corresponding positive-sense mRNAs.[15]
Release
The replicated positive-sense genomic RNA becomes the genome of the progeny viruses. The mRNAs are gene transcripts of the last third of the virus genome after the initial overlapping reading frame. These mRNAs are translated by the host's ribosomes into the structural proteins and a number of accessory proteins.[15] RNA translation occurs inside the endoplasmic reticulum. The viral structural proteins S, E, and M move along the secretory pathway into the Golgi intermediate compartment. There, the M proteins direct most protein-protein interactions required for assembly of viruses following its binding to the nucleocapsid.[22] Progeny viruses are then released from the host cell by exocytosis through secretory vesicles.[22]
Transmission
The interaction of the coronavirus spike protein with its complement host cell receptor is central in determining the tissue tropism, infectivity, and species range of the virus.[23][24] The SARS coronavirus, for example, infects human cells by attaching to the angiotensin-converting enzyme 2 (ACE2) receptor.[25]
Taxonomy
For a more detailed list of members, see Coronaviridae.
Phylogenetic tree of coronaviruses
The scientific name for coronavirus is Orthocoronavirinae or Coronavirinae.[2][3][4] Coronavirus belongs to the family of Coronaviridae.
Genus: Alphacoronavirus
Species: Human coronavirus 229E, Human coronavirus NL63, Miniopterus bat coronavirus 1, Miniopterus bat coronavirus HKU8, Porcine epidemic diarrhea virus, Rhinolophus bat coronavirus HKU2, Scotophilus bat coronavirus 512
Genus Betacoronavirus; type species: Murine coronavirus
Species: Betacoronavirus 1 (Human coronavirus OC43), Human coronavirus HKU1, Murine coronavirus, Pipistrellus bat coronavirus HKU5, Rousettus bat coronavirus HKU9, Severe acute respiratory syndrome-related coronavirus (SARS-CoV, SARS-CoV-2), Tylonycteris bat coronavirus HKU4, Middle East respiratory syndrome-related coronavirus, Hedgehog coronavirus 1 (EriCoV)
Genus Gammacoronavirus; type species: Infectious bronchitis virus
Species: Beluga whale coronavirus SW1, Infectious bronchitis virus
Genus Deltacoronavirus; type species: Bulbul coronavirus HKU11
Species: Bulbul coronavirus HKU11, Porcine coronavirus HKU15
Evolution
The most recent common ancestor (MRCA) of all coronaviruses has been estimated to have existed as recently as 8000 BCE, though some models place the MRCA as far back as 55 million years or more, implying long term coevolution with bats.[26] The MRCAs of the alphacoronavirus line has been placed at about 2400 BCE, the betacoronavirus line at 3300 BCE, the gammacoronavirus line at 2800 BCE, and the deltacoronavirus line at about 3000 BCE. It appears that bats and birds, as warm-blooded flying vertebrates, are ideal hosts for the coronavirus gene source (with bats for alphacoronavirus and betacoronavirus, and birds for gammacoronavirus and deltacoronavirus) to fuel coronavirus evolution and dissemination.[27]
Bovine coronavirus and canine respiratory coronaviruses diverged from a common ancestor recently (~ 1950).[28] Bovine coronavirus and human coronavirus OC43 diverged around the 1890s. Bovine coronavirus diverged from the equine coronavirus species at the end of the 18th century.[29]
The MRCA of human coronavirus OC43 has been dated to the 1950s.[30]
MERS-CoV, although related to several bat coronavirus species, appears to have diverged from these several centuries ago.[31] The human coronavirus NL63 and a bat coronavirus shared an MRCA 563–822 years ago.[32]
The most closely related bat coronavirus and SARS-CoV diverged in 1986.[33] A path of evolution of the SARS virus and keen relationship with bats have been proposed. The authors suggest that the coronaviruses have been coevolved with bats for a long time and the ancestors of SARS-CoV first infected the species of the genus Hipposideridae, subsequently spread to species of the Rhinolophidae and then to civets, and finally to humans.[34][35]
Alpaca coronavirus and human coronavirus 229E diverged before 1960.[36]
Human coronaviruses
Illustration of SARSr-CoV virion
Coronaviruses vary significantly in risk factor. Some can kill more than 30% of those infected (such as MERS-CoV), and some are relatively harmless, such as the common cold.[15] Coronaviruses cause colds with major symptoms, such as fever, and a sore throat from swollen adenoids, occurring primarily in the winter and early spring seasons.[37] Coronaviruses can cause pneumonia (either direct viral pneumonia or secondary bacterial pneumonia) and bronchitis (either direct viral bronchitis or secondary bacterial bronchitis).[38] The human coronavirus discovered in 2003, SARS-CoV, which causes severe acute respiratory syndrome (SARS), has a unique pathogenesis because it causes both upper and lower respiratory tract infections.[38]
Six species of human coronaviruses are known, with one species subdivided into two different strains, making seven strains of human coronaviruses altogether. Four of these strains produce the generally mild symptoms of the common cold:
Human coronavirus OC43 (HCoV-OC43), of the genus β-CoV
Human coronavirus HKU1 (HCoV-HKU1), β-CoV, its genome has 75% similarity to OC43[39]
Human coronavirus 229E (HCoV-229E), α-CoV
Human coronavirus NL63 (HCoV-NL63), α-CoV
Three strains (two species) produce symptoms that are potentially severe; all three of these are β-CoV strains:
Middle East respiratory syndrome-related coronavirus (MERS-CoV)
Severe acute respiratory syndrome coronavirus (SARS-CoV)
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
The coronaviruses HCoV-229E, -NL63, -OC43, and -HKU1 continually circulate in the human population and cause respiratory infections in adults and children worldwide.[40]
Outbreaks of coronavirus diseases
Severe acute respiratory syndrome (SARS)
Main article: Severe acute respiratory syndrome
Characteristics of human coronavirus strains
MERS-CoV, SARS-CoV, SARS-CoV-2,
and related diseases
MERS-CoVSARS-CoVSARS-CoV-2
DiseaseMERSSARSCOVID-19
Outbreaks2012, 2015,
20182002–20042019–2020
pandemic
Epidemiology
Date of first
identified caseJune
2012November
2002December
2019[41]
Location of first
identified caseJeddah,
Saudi ArabiaShunde,
ChinaWuhan,
China
Age average5644[42][a]56[43]
Sex ratio3.3:10.8:1[44]1.6:1[43]
Confirmed cases24948096[45]1,601,018[46][b]
Deaths858774[45]95,718[46][b]
Case fatality rate37%9.2%6.0%[46]
Symptoms
Fever98%99–100%87.9%[47]
Dry cough47%29–75%67.7%[47]
Dyspnea72%40–42%18.6%[47]
Diarrhea26%20–25%3.7%[47]
Sore throat21%13–25%13.9%[47]
Ventilatory support24.5%[48]14–20%4.1%[49]
Notes
^ Based on data from Hong Kong.
^ Jump up to: a b Data as of 10 April 2020.
vte
In 2003, following the outbreak of severe acute respiratory syndrome (SARS) which had begun the prior year in Asia, and secondary cases elsewhere in the world, the World Health Organization (WHO) issued a press release stating that a novel coronavirus identified by a number of laboratories was the causative agent for SARS. The virus was officially named the SARS coronavirus (SARS-CoV). More than 8,000 people were infected, about ten percent of whom died.[25]
Middle East respiratory syndrome (MERS)
Main article: Middle East respiratory syndrome
In September 2012, a new type of coronavirus was identified, initially called Novel Coronavirus 2012, and now officially named Middle East respiratory syndrome coronavirus (MERS-CoV).[50][51] The World Health Organization issued a global alert soon after.[52] The WHO update on 28 September 2012 said the virus did not seem to pass easily from person to person.[53] However, on 12 May 2013, a case of human-to-human transmission in France was confirmed by the French Ministry of Social Affairs and Health.[54] In addition, cases of human-to-human transmission were reported by the Ministry of Health in Tunisia. Two confirmed cases involved people who seemed to have caught the disease from their late father, who became ill after a visit to Qatar and Saudi Arabia. Despite this, it appears the virus had trouble spreading from human to human, as most individuals who are infected do not transmit the virus.[55] By 30 October 2013, there were 124 cases and 52 deaths in Saudi Arabia.[56]
After the Dutch Erasmus Medical Centre sequenced the virus, the virus was given a new name, Human Coronavirus—Erasmus Medical Centre (HCoV-EMC). The final name for the virus is Middle East respiratory syndrome coronavirus (MERS-CoV). The only U.S. cases (both survived) were recorded in May 2014.[57]
In May 2015, an outbreak of MERS-CoV occurred in the Republic of Korea, when a man who had traveled to the Middle East, visited four hospitals in the Seoul area to treat his illness. This caused one of the largest outbreaks of MERS-CoV outside the Middle East.[58] As of December 2019, 2,468 cases of MERS-CoV infection had been confirmed by laboratory tests, 851 of which were fatal, a mortality rate of approximately 34.5%.[59]
Coronavirus disease 2019 (COVID-19)
Main article: Coronavirus disease 2019
In December 2019, a pneumonia outbreak was reported in Wuhan, China.[60] On 31 December 2019, the outbreak was traced to a novel strain of coronavirus,[61] which was given the interim name 2019-nCoV by the World Health Organization (WHO),[62][63][64] later renamed SARS-CoV-2 by the International Committee on Taxonomy of Viruses. Some researchers have suggested the Huanan Seafood Wholesale Market may not be the original source of viral transmission to humans.[65][66]
As of 10 April 2020, there have been at least 95,718[46] confirmed deaths and more than 1,601,018[46] confirmed cases in the coronavirus pneumonia pandemic. The Wuhan strain has been identified as a new strain of Betacoronavirus from group 2B with approximately 70% genetic similarity to the SARS-CoV.[67] The virus has a 96% similarity to a bat coronavirus, so it is widely suspected to originate from bats as well.[65][68] The pandemic has resulted in travel restrictions and nationwide lockdowns in several countries.
Other animals
Coronaviruses have been recognized as causing pathological conditions in veterinary medicine since the 1930s.[9] Except for avian infectious bronchitis, the major related diseases have mainly an intestinal location.[69]
Diseases caused
Coronaviruses primarily infect the upper respiratory and gastrointestinal tract of mammals and birds. They also cause a range of diseases in farm animals and domesticated pets, some of which can be serious and are a threat to the farming industry. In chickens, the infectious bronchitis virus (IBV), a coronavirus, targets not only the respiratory tract but also the urogenital tract. The virus can spread to different organs throughout the chicken.[70] Economically significant coronaviruses of farm animals include porcine coronavirus (transmissible gastroenteritis coronavirus, TGE) and bovine coronavirus, which both result in diarrhea in young animals. Feline coronavirus: two forms, feline enteric coronavirus is a pathogen of minor clinical significance, but spontaneous mutation of this virus can result in feline infectious peritonitis (FIP), a disease associated with high mortality. Similarly, there are two types of coronavirus that infect ferrets: Ferret enteric coronavirus causes a gastrointestinal syndrome known as epizootic catarrhal enteritis (ECE), and a more lethal systemic version of the virus (like FIP in cats) known as ferret systemic coronavirus (FSC).[71] There are two types of canine coronavirus (CCoV), one that causes mild gastrointestinal disease and one that has been found to cause respiratory disease. Mouse hepatitis virus (MHV) is a coronavirus that causes an epidemic murine illness with high mortality, especially among colonies of laboratory mice.[72] Sialodacryoadenitis virus (SDAV) is highly infectious coronavirus of laboratory rats, which can be transmitted between individuals by direct contact and indirectly by aerosol. Acute infections have high morbidity and tropism for the salivary, lachrymal and harderian glands.[73]
A HKU2-related bat coronavirus called swine acute diarrhea syndrome coronavirus (SADS-CoV) causes diarrhea in pigs.[74]
Prior to the discovery of SARS-CoV, MHV had been the best-studied coronavirus both in vivo and in vitro as well as at the molecular level. Some strains of MHV cause a progressive demyelinating encephalitis in mice which has been used as a murine model for multiple sclerosis. Significant research efforts have been focused on elucidating the viral pathogenesis of these animal coronaviruses, especially by virologists interested in veterinary and zoonotic diseases.[75]
Domestic animals
Infectious bronchitis virus (IBV) causes avian infectious bronchitis.
Porcine coronavirus (transmissible gastroenteritis coronavirus of pigs, TGEV).[76][77]
Bovine coronavirus (BCV), responsible for severe profuse enteritis in of young calves.
Feline coronavirus (FCoV) causes mild enteritis in cats as well as severe Feline infectious peritonitis (other variants of the same virus).
the two types of canine coronavirus (CCoV) (one causing enteritis, the other found in respiratory diseases).
Turkey coronavirus (TCV) causes enteritis in turkeys.
Ferret enteric coronavirus causes epizootic catarrhal enteritis in ferrets.
Ferret systemic coronavirus causes FIP-like systemic syndrome in ferrets.[78]
Pantropic canine coronavirus.
Rabbit enteric coronavirus causes acute gastrointestinal disease and diarrhea in young European rabbits. Mortality rates are high.[79]
Porcine epidemic diarrhea virus (PED or PEDV), has emerged around the world.[80]
Genomic cis-acting elements
In common with the genomes of all other RNA viruses, coronavirus genomes contain cis-acting RNA elements that ensure the specific replication of viral RNA by a virally encoded RNA-dependent RNA polymerase. The embedded cis-acting elements devoted to coronavirus replication constitute a small fraction of the total genome, but this is presumed to be a reflection of the fact that coronaviruses have the largest genomes of all RNA viruses. The boundaries of cis-acting elements essential to replication are fairly well-defined, and the RNA secondary structures of these regions are understood. However, how these cis-acting structures and sequences interact with the viral replicase and host cell components to allow RNA synthesis is not well understood.[81][5]
Genome packaging
The assembly of infectious coronavirus particles requires the selection of viral genomic RNA from a cellular pool that contains an abundant excess of non-viral and viral RNAs. Among the seven to ten specific viral mRNAs synthesized in virus-infected cells, only the full-length genomic RNA is packaged efficiently into coronavirus particles. Studies have revealed cis-acting elements and trans-acting viral factors involved in the coronavirus genome encapsidation and packaging. Understanding the molecular mechanisms of genome selection and packaging is critical for developing antiviral strategies and viral expression vectors based on the coronavirus genome.[81][5]
The High-speed Marine Transport Co., Ltd.'s passenger and cargo ship MV Hakuou, chartered by Japan Ministry of Defense, is moored at Yokosuka Naval Base, Japan, February 4, 2020, during a disaster relief operation.
At first, the ship was planned to be used as accommodation facility for Japanese people returning from China on charter flights due to Novel Coronavirus (COVID-19) outbreak, but later the plan was changed and the ship was used as accommodation facility for Japan Self-Defense Force's officers dedicated to a life support mission for passengers waiting for the quarantine period until February 19, 2020 on the cruise ship MV Diamond Princess (IMO: 9228198, MMSI: 235103359) where COVID-19 outbreak occured.