The Food and Drug Administration is likely to authorize distribution of the Pfizer-BioNTech COVID-19 vaccine soon. But trials of the vaccine so far have excluded pregnant women.
Among the first in line to get the vaccine, this is a significant exclusion. Three-quarters of health workers are women, including more than 85% of nurses. The Centers for Disease Control and Prevention estimate that 330,000 health care staff members could be pregnant or recently postpartum at the time of the vaccine’s implementation.
Studies have found that pregnant people are at increased risk for severe COVID-19. As NPR’s Richard Harris reported, vaccine researchers do not expect vaccines to put mothers or newborns at risk, but unfortunately, pregnancy-specific data does not yet exist. Studies involving pregnant people are not expected to begin enrollment until the first quarter of 2021.
Why aren’t pregnant women part of vaccine trials?
Denise Jamieson is Chair of the Department of Gynecology and Obstetrics at Emory University School of Medicine and is part of the American College of Obstetricians and Gynecologists Task Force on COVID-19.
She says pregnant women are routinely excluded from most clinical trials in the US because it simplifies the conduct of trials: “Actually, there are very few drugs, for example, that are approved during pregnancy because it is easier, basically. It’s easier to exclude pregnant women because when you include pregnant women, you have to worry about the health of the woman as well as the development of the fetus and the baby. “
Pregnant women have received vaccinations for decades, he says, with little trouble. “We generally do not administer live virus vaccines during pregnancy because there is a theoretical risk that the live virus will be transmitted and infect the fetus,” says Jamieson. “But with the exception of the smallpox vaccines, there have really been very few problems with the vaccines.”
The Pfizer and Moderna vaccines rely on new messenger RNA technology, but Jamieson doesn’t see any scientific cause for concern there. With these vaccines, he says, the mRNA basically gets into muscle cells, provides information to the cells on how to make the peak protein of the SARS-CoV-2 virus, and then the mRNA is rapidly degraded.
“So I can’t think of any potential or theoretical reason to be concerned about mRNA vaccines during pregnancy, with the only exception that when a vaccine is given and an immune response is generated, you may have a fever. And the fever is something we try to avoid during pregnancy, “she says. “Therefore, it may be important that if women have a fever, they treat [it] with acetaminophen, which is what we recommend for fever during pregnancy. “
“Knowing what I know about him [mRNA vaccine’s] mechanism of action, I would anticipate that this vaccine should be very safe during pregnancy, “says Jamieson.
Ruth Faden, founder of the Johns Hopkins University Bioethics Institute, says it’s not an ideal situation: launching a vaccine that has not been tested in pregnant people. “We are in a situation right now where we have to move on with information that we absolutely do not have. Understandably we do not have data on pregnant women yet, but it would be better if we did,” he said. told NPR Weekend edition.
The American College of Obstetricians and Gynecologists, or ACOG, has urged CDC’s Advisory Committee on Immunization Practices not to exclude pregnant and lactating people from high-priority populations for COVID-19 vaccine assignment. The group notes that pregnant people are at high risk of contracting the coronavirus for multiple reasons: “In addition to being a self-identified risk group, more than half of pregnant women are also in another priority category, including frontline workers and those with underlying conditions. “
In Britain, regulators have advised against offering the Pfizer-BioNTech vaccine to pregnant or lactating people. They also caution that “women of childbearing potential should be advised to avoid pregnancy for at least 2 months after the second dose.”
Jamieson says Canada’s approach is better than the UK’s. “Pfizer’s instructions in Canada specify that pregnant women should speak with their health care provider,” he says. “It is listed under one of the things that ‘if you have this condition, talk to your healthcare provider,’ but they don’t list it as a contraindication, and pregnant women are being vaccinated with the Pfizer vaccine in Canada.”
What about breastfeeding?
In the United States, the Society for Maternal-Fetal Medicine has stated that “there is no biological plausibility for the exclusion of lactating women from these trials.”
“For some reason that doesn’t make any sense to me, lactating and pregnant women are always grouped in a group,” says Jamieson. “They’re actually two very different groups, and there’s an even less theoretical reason to be concerned about breastfeeding women. We routinely give live viral vaccines (measles, mumps, and rubella vaccine) to breastfeeding women. And that it is a live viral vaccine. “
Dr. Laura Riley, chair of the Department of Obstetrics and Gynecology at Weill Cornell Medicine and chair of ACOG’s immunization committee, agrees.
“The idea of this mRNA vaccine getting into breast milk, really? We want to prevent people from dying and get the vaccine. I would hate to see a woman who is breastfeeding stop so she can get the vaccine.” Riley says.
Considerations for getting the vaccine during pregnancy
Jamieson is hopeful, based on public comments from the FDA, that the agency will do what ACOG has recommended: If a pregnant woman would be offered the opportunity to get vaccinated, she should speak to her healthcare provider and possibly get vaccinated.
The FDA may decide that pregnant people should not get the vaccine. But most likely, Faden says, it will be up to them and their doctors to decide what is best.
So, assuming they have a choice, how should pregnant people decide to get vaccinated against the coronavirus?
Faden recommends that you assess your individual risk: the risk of becoming infected in the first place and the risk of becoming seriously ill if you become infected with the virus.
“A disproportionate burden of disease during pregnancy appears to be affecting low-income women, women from communities of color, women who are otherwise disadvantaged,” she says. “There is nothing about pregnancy that is protective.”
In consultation with a healthcare provider, Jamieson says, the pregnant person can then put that risk assessment together with what is known about mRNA vaccines, what is known about other vaccines during pregnancy, and decide what makes sense.
Riley says she is being inundated with calls from pregnant healthcare workers asking what they should do: “I work in an ICU, I work in a COVID unit, should I get the vaccine?” they ask him.
“It’s easy to say it’s painful, but they’re the front-line workers, whether they’re nurses, doctors, or sitting at the front desk,” Riley says. “I worry about women in the supermarket every day. At least if you’re in a hospital, you have PPE. But if you work in a supermarket and take the train to work, a lot of those people are pregnant or are thinking of getting pregnant.”
In the absence of data from vaccine trials in pregnant people, the decision to get vaccinated will likely come down to that conversation between the pregnant person and the healthcare provider.
“People who are pregnant have a lot to worry about and we don’t need to add to people’s stress,” Faden says. “Unfortunately, this is a stressful circumstance. Take a deep breath, and given the option, it may make sense to have this vaccine. It may not.”