July 20, 2017
Ever since the shocking realization in 1961 that the morning sickness pill thalidomide caused shortened limbs in babies, doctors have been extremely wary of giving any medicine to a pregnant woman—and testing experimental drugs has raised even more concerns. But the recent discovery that exposure to Zika virus in utero can cause severe brain damage and other problems in children triggered an international effort to develop a vaccine for pregnant women. A new report written by an ad hoc group of prominent researchers, bioethicists, clinicians, and drugmakers concludes that pregnant women should be included in trials of Zika vaccines, once safety in animals and nonpregnant adults is demonstrated. The risk/benefit issues spelled out in the report also apply to experiments with maternal immunization for other diseases, which are winning increasing support.
Researchers have been too reticent to include pregnant women in clinical trials of vaccines, contends the working group behind the report. “Even for the vaccines we now recommend in pregnancy, pertussis and flu, the original trials did not include pregnant women,” says Carleigh Krubiner, a bioethicist at the Johns Hopkins Berman Institute of Bioethics in Baltimore, Maryland, who is part of the group, which was sponsored by the London-based Wellcome Trust. “This project is trying to be more proactive.”
The half-dozen Zika vaccine trials now taking place only enroll women of childbearing age who are on contraception or have a sterile male partner. That is appropriate, according to the risk/benefit analyses spelled out in the report, as these early studies assess only safety and basic immune responses.