By Anne Drapkin Lyerly, Carleigh Krubiner, Ruth Faden


This op-ed was originally published by the Baltimore Sun.


The rapid spread of the Zika virus — and its now clear association with microcephaly in babies exposed prenatally — has put extraordinary pressure on the research community to develop a vaccine as rapidly as possible. But accelerating the development of this vaccine is not only scientifically and logistically complicated, it is ethically complicated.


Pregnant women are at the crux of Zika’s most devastating consequences. Their needs must be uppermost in Zika prevention plans. While this will not be easy, the knee-jerk response that research with pregnant women is too complex to contemplate is not acceptable.


Current recommendations for women to delay or avoid pregnancy are unfair and unrealistic. In many areas hit hardest by Zika, women have limited access to contraception; there are, moreover, high rates of unplanned pregnancy worldwide. Preventing pregnancy may be the right course for some women, and preventing Zika in women before they get pregnant is critical. But these responses cannot be the whole answer. If we are serious about addressing the devastating impacts of Zika on normal brain development (Zika congenital syndrome), we must consider all approaches to preventing infection during pregnancy. This will require, at the very least, conscientious consideration of the role of pregnant women in the vaccine development agenda.


No doubt research with pregnant women is complicated. But ethical research with pregnant women is not impossible. Some might propose avoiding these complexities by testing vaccines in non-pregnant individuals, with a promise to collect safety data among pregnant women later. Indeed, this has been the approach to vaccine and medication testing in pregnancy for years. But it falls short, with potentially devastating consequences.


First, pregnancy changes physiology, including immune system functioning. As a result pregnant women may have reduced immune responses to a vaccine compared to non-pregnant adults. We cannot assume that a vaccine that works at a certain dose in non-pregnant adults will work at the same dose in pregnant women.


Second, there is the question of fetal safety. Vaccines present a particularly complicated picture: “live attenuated” vaccines are avoided in pregnancy due to theoretical risks of fetal harm. Yet they are among the most promising under development for Zika. Weighing scientific promise with safety considerations, especially when both are uncertain, is ethically and scientifically challenging. But excluding pregnant women or their interests from immediate consideration only shifts fetal risk out of a highly controlled research context and into the clinical and public health setting — where, if fetal risk exists, more babies will likely be affected.


Third, in public health emergencies, time is of the essence. Yet years, sometimes decades, pass between drug approval for the general population and safety determination for pregnant women. Rubella — a live attenuated vaccine — is contraindicated in pregnancy, even though 40-plus years after approval no cases of congenital rubella have been reported among more than 1,000 women inadvertently vaccinated during pregnancy. Fetal safety should be assessed early in the process with determinations based on evidence, rather than leaving mothers (and fathers) to worry.


Research with pregnant women can be done — ethically and in accordance with international guidelines. During the H1N1 epidemic, the National Institutes of Health took an important step forward, prospectively studying H1N1 vaccine in 120 pregnant women. This groundbreaking effort helpfully informed dosing guidance and provided further evidence of safety.


As key global partners mobilize around Zika vaccine development, there is a critical window to challenge the status quo and explore ethically responsible strategies to address the health needs of pregnant women in research. With generous funding from the Wellcome Trust to four universities, including Johns Hopkins Berman Institute of Bioethics, our group will engage experts in vaccine science, women’s health, ethics, law and health policy to develop guidance on how pregnant women can and should be ethically engaged in the research agenda for Zika and other public health emergencies.


Pregnancy is no magic bullet against illness. Pregnant women get sick, and sick women get pregnant. The Zika epidemic is a poignant reminder of this and urges that we prioritize — not exclude — pregnant women when developing ways to stop this terrible virus. Research with pregnant women is not the ethical nightmare it’s made out to be. The real nightmare would be if in this push for a Zika vaccine, we miss the opportunity to develop evidence-based guidance for how best to prevent Zika in pregnancy. We need reliable information so that women can feel confident and know, not just hope, that they have chosen a safe and effective way to protect themselves and their future children.


Anne Drapkin Lyerly ( is associate director of the University of North Carolina Center for Bioethics and Carleigh Krubiner ( is faculty research scholar at Johns Hopkins Berman Institute of Bioethics, where Ruth Faden is the director.


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Carleigh Krubiner
Ruth Faden

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