20220926

www.nih.gov/news-events/news-releases/study-confirms-link...

 

Study confirms link between COVID-19 vaccination and temporary increase in menstrual cycle length

Large NIH-funded study included participants in North America and Europe.

 

A large international study has confirmed the findings of a previous U.S. study that linked COVID-19 vaccination with an average increase in menstrual cycle length of less than one day. The increase was not associated with any change in the number of days of menses (days of bleeding). Funded by the National Institutes of Health, the new study included data from nearly 20,000 people from Canada, the United Kingdom, the United States, Europe and other parts of the world who received any of nine different vaccines. For most study participants, the increase resolved in the cycle following vaccination.

 

The study’s principal investigator was Alison Edelman, M.D., M.P.H., of Oregon Health & Science University in Portland. It appears in the BMJ Medicine.

 

“These findings provide additional information for counseling women on what to expect after vaccination,” said Diana Bianchi, M.D., director of NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD). “Changes following vaccination appear to be small, within the normal range of variation, and temporary.”

 

NICHD and NIH’s Office of Research on Women’s Health funded the study, which was part of $1.67 million awarded to five institutions to explore potential links between COVID-19 vaccination and menstrual changes.

 

A change in cycle length of less than eight days is considered within the normal range of variation. Although small menstrual changes may not be meaningful to health care professionals and researchers, the study authors wrote, perceived changes in a bodily function linked to fertility may be alarming to those experiencing it and could contribute to vaccine hesitancy.

 

Researchers analyzed de-identified data from the fertility tracking app, Natural Cycles. Users of the app provided it information on their temperature and their menstrual cycles. They also had the option to consent to the use of their de-identified data for research. Worldwide rollout of COVID-19 vaccines allowed the study authors to expand on their original study of people in the United States. The study included data from participants throughout the world, but most were from the United Kingdom (32%), the United States and Canada (29%) and Europe (34%). In addition to the messenger RNA COVID-19 vaccines (Pfizer-BioNTech and Moderna), participants received COVID-19 vaccines made from engineered viruses (AstraZeneca, Covishield, Janssen/Johnson & Johnson and Sputnik), and inactivated viruses (Covaxin, Sinopharm, and Sinovac).

 

A total of 19,622 individuals participated. Of these, 14,936 were vaccinated and 4,686 were not. The researchers analyzed data on at least three consecutive cycles before vaccination and at least one cycle after. Data from at least four consecutive cycles were analyzed over a similar time interval for unvaccinated participants.

 

On average, vaccinated people experienced an increase of less than one day in each cycle in which they were vaccinated: a .71 day increase after the first dose and a .56 day increase after the second dose. Participants who received both doses in a single cycle had a 3.91 day increase in cycle length. After vaccination, cycle length had increased by only .02 days for individuals who received one dose per cycle, and .85 days for individuals who received two doses in one cycle, compared to participants who were not vaccinated. Changes in cycle length did not differ according to the type of vaccine received.

 

Of the total, 1,342 participants experienced a change in cycle length of eight or more days, comprising 6.2% of vaccinated individuals and 5.0% of unvaccinated individuals. Women who were younger and who had longer cycle length before vaccination were more likely to experience the increase.

 

The authors called for future studies on other aspects of vaccination-linked changes to menstrual cycles, such as unexpected vaginal bleeding and menstrual flow and pain. They also called for studies to determine the physical reasons why such changes might occur.

 

www.cnn.com/2022/09/27/health/uk-fall-wave-covid-us/index...

 

Rising Covid-19 cases in the UK may be a warning for the US

 

There are signs that the United Kingdom could be heading into a fall Covid-19 wave, and experts say the United States may not be far behind.

 

A recent increase in Covid-19 cases in England doesn’t seem to be driven by a new coronavirus variant, at least for now, although several are gaining strength in the US and across the pond.

 

“Generally, what happens in the UK is reflected about a month later in the US. I think this is what I’ve sort of been seeing,” said Dr. Tim Spector, professor of genetic epidemiology at Kings College London.

 

Spector runs the Zoe Health Study, which uses an app to let people in the UK and US report their daily symptoms. If they start to feel bad, they take a home Covid-19 test and record those results. He says that about 500,000 people are currently logging their symptoms every day to help track trends in the pandemic.

 

Spector says the study, which has been running since the days of the first lockdown in England in 2020, has accurately captured the start of each wave, and its numbers run about one to two weeks ahead of official government statistics.

 

After seeing a downward trend for the past few weeks, the Zoe study saw a 30% increase in reported Covid-19 cases within the past week.

 

“Our current data is definitely showing this is the beginning of the next wave,” Spector said.

 

On Friday, that increase was reflected in official UK government data too, although it was not as large as the increases reported by Zoe loggers.

 

Data from the National Health Service showed that after falling for nearly two months, the seven-day average of new cases in England and Wales rose 13% for the week ending September 17 over the week before. The seven-day average of hospitalizations was up 17% in the week ending September 19 compared with the week prior.

 

The data aligns with what models have predicted would happen in both the UK and the US.

 

“They predicted that we’d get a June to July peak and then there’d be a month where nothing happened in August and then it would flatten in in August and September and then start again in October. So it’s exactly matching what the modelers have have been predicting,” Spector said.

 

In the US, some models have predicted that Covid-19 cases will begin to rise again in October and continue to increase into the winter. Experts are hopeful that because most of the population now has some underlying immunity to the coronavirus, this wave would be less deadly than we’ve seen in previous winters.

 

Is this a blip or a wave?

 

It’s not clear what’s driving the increase in the UK or whether it will be sustained.

 

“These trends may continue for more than a week or two, or they may not,” said Kevin McConway, emeritus professor of applied statistics at the Open University in Milton Keynes, England.

 

Broken down by age, he says, there are clear increases among adolescents who are around middle school age and younger adults, those 25 through 34.

 

“It wouldn’t be surprising if there were some increase in infection as people come back from summer holidays and as the schools reopen,” McConway said in a statement to the nonprofit Science Media Centre. “Even if it is, there’s certainly no clear indication yet that it will continue.”

 

He’s not the only one who needs to see more data before calling this the start of a new wave.

 

“Question one is, how significant is that rise? Is it, for instance, the beginning of something, a new wave, or is this a temporary blip because of all of the getting together around the Queen’s funeral and other events that have been going on?” said Dr. Peter Hotez, who co-directs the Center for Vaccine Development at Texas Children’s Hospital in Houston.

 

A second important question will be whether the increase is being driven by a new variant.

 

“That’s the worst possible situation. Because historically, when that situation occurs in the UK, it’s reflected within a matter of weeks in the United States,” Hotez said. “That was true of the Alpha wave; that was true of the Delta wave; that was true of Omicron and its subvariants.”

 

The role of new variants

 

That’s where the US may catch a break this time around.

 

Instead of new variants, Christina Pagel, a professor of operational research at University College London, thinks cases are going up in the UK because of a combination of waning immunity and behavioral changes.

 

Many people in the UK are several months past their last Covid-19 booster or infection, and government statistics show that just 8% of adults 50 and older have gotten an Omicron-specific vaccine since the government started its fall vaccination campaign in September. School and work have fully resumed after the summer holidays, and people are spending more time indoors as the temperature drops.

 

Immunity is also waning in the United States, and Americans have also been slow to get boosted. Just 35% of those for whom a booster is recommended have had one, according to CDC data.

 

The updated boosters in the US are slightly different from the ones in the UK. The UK is using vaccines that have been updated to fight the original version of Omicron, which is not circulating anymore. US boosters have been updated to fight the BA.4 and BA.5 subvariants, which are currently causing infections both here and abroad. It’s not clear whether the strain differences will have an effect on cases or disease severity.

 

There are a mix of new variants – offshoots of BA.4 and BA.5 – that are waiting in the wings. They represent just a small proportion of total cases, but several are growing against BA.5, which is still dominating transmission.

 

“It is very likely that these will accelerate current increases and cause a substantial wave in October” in the UK, Pagel said in an email to CNN.

 

Other experts agree with that assessment.

 

“There is talk about a bunch of lineages with concerning mutations, including BA.2.75, BQ.1.1, etc, but none of these are of high enough frequency in the UK right now to be driving the change in cases,” Nathan Grubaugh, who studies the epidemiology of microbial diseases at the Yale School of Public Health, said in an email to CNN.

 

He says the mix of variants in the UK seems to be much the same as it is in the US, at least for now.

 

“We are seeing the increase in many respiratory viruses right now in the US, so it’s not a stretch to think that a new COVID wave (or ripple) will be coming soon,” he wrote.

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