What we know about COVID-19 seems to change by the minute.
It’s understandable, given the massive scale of the pandemic. Right now, more than 150 million cases have been confirmed around the world. And even a year into the pandemic, the virus and ways to address it are still relatively new to the medical world, so researchers are learning as they go.
The amount of information out there about the coronavirus is dizzying. It’s hard to keep track of what’s known, what’s a myth and what guidance we should follow. That’s why we’ve rounded up five of the most important new things we learned about COVID-19 in April:
1. That blood clots have been linked to the Johnson & Johnson vaccine — but they’re extremely rare.
The single-shot Johnson & Johnson vaccine grabbed a lot of headlines in April when the Centers for Disease Control and Prevention and Food and Drug Administration called for a temporary pause on distribution of the vaccine.
The groups stated that “out of an abundance of caution” they were looking into a handful of incidents in which some recipients (all women, most under the age of 50) developed a rare disorder involving blood clots and low blood platelets within two weeks of receiving their shot.
The CDC and FDA have now reported that there are 15 known cases of women who have experienced this extremely rare outcome within two weeks of vaccination. That means it is an outcome seen in 1.9 people per every million people given the shot.
Given how rare the cases are — and the risk that COVID-19 continues to pose — the groups reapproved the vaccine, though it now carries a warning about the extremely rare outcome.
“The benefits of the vaccine continue to outweigh these risks, and we now have detailed information in the labeling that alerts to these risks,” EMA Executive Director Emer Cooke said. “We’re confident that it can be rolled out appropriately.”
2. There *could* be a link between vaccination and menstrual cycle changes.
In April, many anecdotes began bubbling up on Twitter and in news stories about women who have experienced period-related changes after vaccination. Specifically, some women report they are experiencing increased flow as well as late menstrual cycles.
Health experts don’t really have much (or really any) concrete information about a possible vaccination/menstruation link at this point, in part because period-related symptoms weren’t tracked during the clinical trials. But also, periods can be a really challenging thing to study.
“Menstruation is a complex process, which can be influenced by many factors, such as environmental changes, stress, sleep and some medications,” Dr. Danielle Jones, a board-certified obstetrician-gynecologist based in Texas, previously told HuffPost.
Ultimately, while the potential changes are something that women’s health experts are paying more attention to, and that women themselves might want to be aware of, there’s no real concern that these could be lasting, serious changes.
In general, women who do experience heavier menstrual cycles after they receive the COVID-19 vaccine should stick to what’s typically recommended when grappling with a heavy period, like taking an anti-inflammatory over-the-counter medication or applying heat.
In addition, anyone who experiences intense symptoms after their vaccine is encouraged to submit a report via the Vaccine Adverse Event Reporting System (VAERS).
3. Pregnant women may be at higher risk for serious outcomes from COVID-19 than previously thought.
COVID-19 might pose a greater risk to pregnant women and their babies than previously understood, an April study warned.
“Women with COVID-19 during pregnancy were over 50% more likely to experience pregnancy complications (such as premature birth, pre-eclampsia, admission to intensive care and death) compared to pregnant women unaffected by COVID-19,” said study researcher Dr. Aris Papageorghiou, a professor of fetal Medicine at the University of Oxford in England in a press statement.
Newborns whose mothers were infected with COVID-19 were also nearly three times more likely to develop severe medical complications, most of which were due to preterm birth.
However, those increased risks appear to be concentrated in women who develop symptomatic COVID-19.
“The good news, however, is that the risks in symptomless infected women and non-infected women were similar,” Papageorghiou added.
And experts stress that COVID-19 vaccines are safe and effective for pregnant women.
4. Younger children really are less likely to spread the virus.
Unfortunately, much of the conversation about children and COVID-19 that has been happening at a policy level and on social media lacks nuance — especially when it comes to how much risk children pose to others.
New research published in April that looked at data from Israel — where schools have opened and closed several times during the pandemic — added some clarity to the the question of how much children contribute to the spread of the coronavirus in their community, finding that younger students (up to age 9) have very low rates of transmission.
“Our study’s findings suggest that children aged 0 to 9 years did not have substantial rates of SARS-CoV-2 infection during school attendance periods, and it may be assumed that they did not have a substantial role in COVID-19 spread either during this period,” the researchers wrote.
They could not, however, confirm that the same was true of adolescents, and recommended that: “It is probably safer to resume school attendance for youths aged 10 to 19 years only when the epidemic is under control and after implementation of steps to decrease spread in schools.”
5. COVID-19 vaccines don’t pose an increased risk for facial paralysis.
In initial clinical trials for the Pfizer and Moderna vaccines, a handful of participants developed Bell’s palsy — a condition that causes sudden weakness on half of the face, often in response to a viral infection.
Because of that, the FDA has been monitoring people who’ve received those vaccines for potential instances of paralysis since last winter, while emphasizing all along that it does not consider Bell’s palsy to be a side effect of the vaccines.
New research published in April supports that claim, finding there is no sign that COVID-19 vaccines should increase a person’s risk for developing facial paralysis, or related events (like facial spasms). The researchers analyzed more than 133,000 instances of adverse vaccine reactions that were reported to the World Health Organization, and found that less than 1% were related to facial paralysis.
They note that that is on par with what is reported in relation to other viral vaccines, as well as among those who receive the flu shot.
“The risk,” the researchers wrote in the JAMA Internal Medicine, “is likely very low, as with other viral vaccines.”
Experts are still learning about COVID-19. The information in this story is what was known or available as of publication, but guidance can change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.