Clinical Trials and Administration of Zika Virus Vaccine in Pregnant Women: Lessons (that Should Have Been) Learned from Excluding Immunization with the Ebola Vaccine during Pregnancy and Lactation.

David Schwartz

doi:10.3390/vaccines6040081

Abstract

As evidenced from recent epidemics, both Ebola and Zika virus infection are potentially catastrophic when occurring in pregnant women. Ebola virus causes extremely high rates of mortality in both mothers and infants; Zika virus is a TORCH infection that produces a congenital malformation syndrome and pediatric neurodevelopmental abnormalities. Production of efficacious vaccines has been a public health priority for both infections. Unfortunately, during the clinical trials and subsequent deployment of a vaccine for the Ebola virus, pregnant and lactating women were, and continue to be, excluded from receiving the life-saving vaccine. The most serious consequence of Zika virus infection, congenital Zika syndrome, results from fetal infection during pregnancy. Thus, pregnant women have a major stake in the ongoing development of a vaccine for Zika virus. The exclusion of pregnant women from the development, clinical trials and administration of a potential Zika vaccine unfairly deprives them and their infants of the protection they need against this potentially catastrophic intrauterine infection. When creating policy about these issues, it is important to critically evaluate vaccine safety in pregnancy in the context of the substantial risk of infection for the pregnant woman and her fetus in the absence of immunization.

Highlights

IntroductionThe Zika virus outbreak was first recognized in Northeastern Brazil in early 2015, spread rapidly through South American countries, into Central America and the Caribbean, became a global pandemic, and occurs as an endemic arboviral infection throughout much of the Western hemisphere [1]
The Zika virus outbreak was first recognized in Northeastern Brazil in early 2015, spread rapidly through South American countries, into Central America and the Caribbean, became a global pandemic, and occurs as an endemic arboviral infection throughout much of the Western hemisphere [1].Spread of the virus is not just limited to the natural ecology of its major insect vector, the mosquitoAedes aegypti, because sexual transmission of this flavivirus has been found to occur from males to their female partners [2]
Guillain-Barré syndrome has been strongly associated with Zika virus infection [3], its occurrence is rare, and for the overwhelming majority of non-pregnant adults, the infection is of little medical consequence beyond a transient febrile illness accompanied by rash, conjunctivitis, muscle and joint pains, and headache

Summary

Introduction

The Zika virus outbreak was first recognized in Northeastern Brazil in early 2015, spread rapidly through South American countries, into Central America and the Caribbean, became a global pandemic, and occurs as an endemic arboviral infection throughout much of the Western hemisphere [1]. There is little doubt that the development of an effective Zika vaccine will have its greatest benefit in preventing pregnant women from acquiring the infection and transmitting the virus to their unborn infants This population has historically been excluded from clinical testing of experimental vaccines—potential harm to the fetus, physiological complexity of pregnancy, and the threat of punitive legal actions have all been cited as some of the reasons contributing to the exclusion of pregnant women from clinical vaccine trials, as well as receiving them following their approval for use. The previous policies of exclusion of pregnant and lactating women were once again implemented, excluding these women from receiving the potentially life-saving vaccine The continuance of this policy following the West African epidemic, when pregnant women and children had not been permitted to receive experimental antiviral drugs or vaccines, was considered to be indefensible by some in the public health community [48,49,51], especially since there had never been a mother-infant pair that survived Ebola infection.

Are Pregnant Women Willing to Receive a Hypothetical Zika Virus Vaccine?

Findings

Conclusions