Skip to Main Content

On Thursday, the FDA will review the near-term fate of the Pfizer/BioNtech Covid-19 vaccine. It is likely that the FDA will grant emergency use authorization for the vaccine, just as its British regulatory counterpart, the Medicines and Healthcare products Regulatory Agency (MHRA), did last week.

The FDA should part company with the MHRA, however, when it comes to use of the vaccine by pregnant and lactating people. The MHRA has advised against offering the vaccine to those who are pregnant and breastfeeding, regardless of their circumstances. As the FDA develops its position, we urge it to consider more permissive language that acknowledges information gaps but still permits some high-risk pregnant or lactating individuals to get the vaccine.


We are especially concerned about pregnant or lactating people who are members of the health workforce. Millions of health workers are likely to be offered Covid-19 vaccines over the coming weeks. In the U.S., women make up three-quarters of full-time, year-round workers in health care occupations — more than 90% of registered nurses are female — and it is estimated as many as 330,000 of these health workers will be pregnant or breastfeeding as initial doses of vaccine are being distributed.

We recognize that regulators, public health agencies, and the external committees that advise them are in a tough position. Both the pathogen and the vaccine platform are novel, and few data specific to pregnancy and the vaccine platform are currently available. While developmental and reproductive toxicity (DART) studies with animal models are now underway, data will not be available in time for this week’s deliberations about the Pfizer vaccine or next week’s deliberations about the Moderna vaccine.

To date, pregnant people have been excluded from Operation Warp Speed Phase 3 trials. Studies that include pregnant individuals are not expected to start enrollment until the first quarter of 2021.


We sympathize with decision-makers who must take a position about a brand-new kind of vaccine without much-needed data specific to pregnancy and lactation. In the absence of pregnancy-specific data, we agree that it is premature to recommend that pregnant and lactating individuals should be offered the vaccine. But we disagree with the position of the U.K. authorities that may make it impossible for pregnant or lactating health workers to get the vaccine regardless of their circumstances.

Not all pregnant or lactating health workers face the same risks of exposure or progression to severe disease. Some are at higher risk of contracting the infection because of their occupational roles or their life circumstances. Some are at greater risk of serious outcomes from Covid-19 because they have comorbidities such as diabetes or hypertension, in addition to being pregnant. Some cannot afford to take leave from work. Others cannot be transferred to lower-risk roles because of surge demands on their health care systems.

A permissive regulatory position would make it possible for pregnant and lactating health workers to decide in consultation with their obstetrical providers whether it is — or is not — in their and their baby’s interest to be vaccinated. It would also allow relevant professional medical societies, such as the American College of Obstetrics and Gynecology and the Society for Maternal Fetal Medicine, alongside the Advisory Committee on Immunization Practices, to issue more tailored and nuanced guidance on pregnancy and lactation in response to the evolving state of the evidence.

Leaving the door open to vaccinating pregnant and lactating health workers also recognizes the very real pressure on our health system to sustain the Covid-19 response as case counts continue to escalate. If we are unable to offer vaccines to pregnant or lactating frontline health workers, it is incumbent upon health care systems to offer them alternative protection strategies such as shielding, reassignment, or paid leave. Yet this may not be a viable strategy for most health care facilities, which cannot afford to operate without a significant portion of their workforce.

A restrictive policy would not only deny pregnant and lactating individuals the opportunity to work with the same protection afforded their co-workers, but would further strain available human health resources over the next few months, when pandemic cases — and the need for health care — are peaking.

We also urge the FDA and relevant advisory bodies to view pregnancy and lactation separately. Pregnancy and lactation are biologically distinct conditions, with different considerations regarding risk-benefit assessments, and different complexities as they relate to the maternal-fetal versus the maternal-infant dyad. Although lactation is often lumped together with pregnancy, it would be a mistake to simply apply any determination about vaccine use in pregnancy to those who are breastfeeding. Recommendations for vaccine use in lactation must be based on the relevant information, benefits, and biologically plausible risks as they pertain to breastfeeding individuals and their infants.

Advancing the evidence base for Covid-19 vaccines in pregnancy and lactation must remain a critical priority so policymakers do not find themselves in the same predicament of making decisions without evidence when other types of frontline workers and high-risk groups become eligible. National and state-level vaccine prioritization schemes include plans to expand to other essential workers as soon as adequate doses are available. If things move quickly and smoothly, results of at least the developmental and reproductive toxicity studies for the Pfizer and Moderna vaccines will be available by then.

Over the coming months, data must be secured to make better-informed recommendations and decisions ahead of wider dissemination of Covid-19 vaccines. This includes completing developmental and reproductive toxicity studies as soon as possible for all promising candidates in the pipeline. In addition, Covid-19 vaccines must be evaluated in pregnancy, with near-term efforts to assess safety and immunogenicity as well ongoing work to launch prospective observational studies and registries to establish the safety profile of these new products once they are more widely available. This can and should include collecting data from pregnant health workers who choose to get vaccinated if that option is made available to them.

As a matter of health equity, pregnant and lactating people deserve to have an appropriate evidence base to guide their decisions across their reproductive journeys. This evidence will be crucial as more groups become eligible to receive Covid-19 vaccines, so that teachers, transport workers, and ultimately all pregnant and breastfeeding individuals can make informed decisions about how best to protect themselves and their babies against the threat of Covid-19.

Carleigh B. Krubiner is a policy fellow at the Center for Global Development and associate faculty at the Johns Hopkins Berman Institute of Bioethics. Ruth R. Faden is the founder and inaugural director of the Johns Hopkins Berman Institute of Bioethics. Ruth A. Karron is director of the Johns Hopkins Center for Immunization Research and founder of the Johns Hopkins Vaccine Initiative. They served as the co-principal investigators for the Pregnancy Research Ethics for Vaccines, Epidemics, and New Technologies (PREVENT) Project.

  • This is disgusting. You encourage endangering an unborn baby with a hardly tested vaccine? No. This is the problem the medical community. Pushing untested, unsafe vaccine on people for something with a minute risk for the majority of people. It’s all politics and no healthcare.

    • I’m not sure anyone could be or would be pushed into participating in Phase 3 trials. I think the plea is for the FDA to consider allowing pregnant and lactating women the option to choose to participate in vaccine studies/trial. In that case, it would be each individual mother choosing whether or not her participation would offer more benefits than drawbacks, to herself and her baby. I can say, for myself, that I would rather have the option to choose to participate (and the option to choose to vaccinate), than to be categorically excluded from studies or administrations of the vaccine. I personally do feel safe exploring inoculation. I hope that distinction about being able to choose to participate &/or vaccinate, clarifies the risks and benefits a bit more? stay safe :).

  • As a pregnant woman, I am glad to read this plea for a balanced and inclusive vaccine policy. I live in NYC and I will never know how many people around me have been exposed to coronavirus; so, I would like to have the opportunity to choose to vaccinate myself, for the sake of my baby.

Comments are closed.