Vaccine research must include pregnant women during COVID and beyond

A doctor criticized online after being photographed getting vaccinated while nine months pregnant. A waitress fired from her restaurant job when she resisted vaccination for fear of what it would do to her fertility. Another pregnant physician who hesitated to receive her shot owing to the lack of clear data. 

The COVID-19 pandemic has been especially hard on mothers and mothers-to-be, who are not only coping with closed schools and childcare centers but also receiving conflicting advice about vaccination — creating a potentially deadly scenario. 

Before changing its guidance after coming under criticism, the World Health Organization had recommended against pregnant women receiving the Moderna or Pfizer-BioNTech vaccines unless they are “at risk of high exposure.” That guidance contradicted that of the Centers for Disease Control, the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine, all of which have said that COVID-19 vaccines should be made available to pregnant and breastfeeding women. The conflict stemmed from the fact that expectant mothers were barred from the vaccine clinical trials. 

While it is understandable that researchers and drug companies want to be cautious about testing vaccines on pregnant and nursing women, they can easily go too far. For decades, the U.S. medical establishment took the paternalistic and overly restrictive position of prohibiting drug research on women of “childbearing potential.” The FDA lifted that ban in the 1990s, but pregnant and nursing women continue to be routinely excluded from many medical trials. Until another rule change took effect in 2019, pregnant women were still classed alongside children as a “vulnerable population.” As a result, around three-quarters of drugs approved since 2000 have hit the market without any data on their effects in pregnant women. 

All of this leaves women and their doctors to make judgment calls on treatment options without reliable scientific data to guide them — and increases the chances that people might fall victim to misinformation campaigns, like one currently burning up social media claiming that the COVID-19 vaccine causes infertility. 

To be clear: There is no evidence for this claim and pregnant women are regularly vaccinated for the flu and other diseases without complications. We even know that some women who were enrolled in COVID-19 vaccine trials became pregnant during or shortly after the trial period.

Yet pregnant women are less likely than non-pregnant women to say they plan to get vaccinated. According to a recent paper from the Human Immunomics Initiative, Pregistry and the COVID Collaborative, less than 45 percent of pregnant Americans are likely to take the vaccine when it becomes available. In fact, the U.S. had one of the lowest vaccination acceptance rates among 16 countries surveyed, ahead of only Russia and Australia. In that same survey, just 52 percent of pregnant women overall indicated an intention to receive the vaccine, compared to 73 percent of non-pregnant women — making clear that vaccine hesitancy among pregnant women is a global concern.

This level of vaccine hesitancy puts the lives of pregnant women at risk. Pregnant women are at higher risk of contracting severe COVID-19, compared to their non-pregnant peers. The virus may also increase the risk of serious pregnancy complications, including preterm birth. With the pandemic still raging across the country, pregnant women urgently need clear, consistent guidance on how to protect themselves and their children. 

It is great news that Pfizer is launching its first COVID-19 vaccine trial for pregnant women — but that trial won’t end until 2023. In the meantime, Moderna, Pfizer, and other companies developing vaccines must prioritize analyzing and publicizing the data they already have on women who became pregnant during vaccine trials, even as they step up more systematic tests. Such data could help beat back conspiracy theories and improve safety perceptions of the vaccine. 

Medical and public health researchers working on development of vaccines and treatments for COVID-19 should also build pregnant women into their study designs as early as possible and prioritize testing on pregnant animal subjects before moving to human trials. 

The PREVENT working group has a comprehensive set of recommendations to better protect the health of pregnant and nursing women at every stage of an epidemic — from preparedness to emergency response — that policymakers at all levels should work to adopt. 

As with all health decisions during pregnancy, women should talk with their doctors about the COVID-19 vaccine — and OB-GYNs should stay abreast of the latest information and developments. Counseling should balance available data on vaccine safety and a woman’s individual risk for infection and severe disease. For pregnant women with pre-existing conditions, those who can’t easily work from home and especially those who work in frontline settings, the risks of contracting SARS-CoV-2 infection are much greater than any risks from the vaccines.

One thing is certain. If pregnant women had been included in studies of COVID-19 vaccines in a timelier manner, perhaps more of them would be planning to get vaccinated — and public health organizations would have been making consistent recommendations from the jump. We urgently need to do better for pregnant women for the duration of the pandemic — and to reform our vaccine research and development practices to serve them better going forward. 

Michelle A. Williams is dean of the Harvard T.H. Chan School of Public Health. Steven Phillips is vice president of Science and Strategy with the COVID Collaborative. Julia W. Wu is a principal investigator and epidemiologist with the Harvard T.H. Chan School of Public Health’s Human Immunomics Initiative.