New Zika virus vaccine protects fetus in pregnant monkeys
A new experimental vaccine against the Zika virus reduces the number of viruses in pregnant Rhesus macaques females, which is injected before conception, produced by researchers at the University of California at Davis.
The study, published in Science Translational Medicine, shows that it is possible to act by vaccine on this virus even before conception as well as birth following exposure to the same virus during pregnancy, as explained by Koen Van Rompay, virologist of the California National Primate Research Center of the University of California and one of the authors of the study.
Exposure to the Zika virus in pregnant women and the consequent infection are in fact associated with very high risks of some serious effects on the fetus in addition to death. Among these are microcephaly and other brain abnormalities so much so that we speak of congenital Zika syndrome. A vaccine that has been approved is not yet available but there are some vaccines, including VRC5283, which is currently in the initial testing phase on humans.
Researchers have in fact injected the vaccine in some female Rhesus macaques. They then had the vaccinated and unvaccinated females stay with the males to start the reproductive phase. The pregnant females were then exposed to the Zika virus during the first and second trimester. The vaccinated females showed a smaller amount of virus in the blood and the virus persisted in the fluid for a shorter duration following exposure. The vaccinated females, unlike the unvaccinated females in the control group, had also suffered no early fetal loss.
Towards the end of their pregnancy, researchers tried to extract the Zika virus from the fetuses of both vaccinated and unvaccinated females. 11 of the 12 fetuses in the unvaccinated control group showed the RNA of the virus still detectable. In all 13 fetuses in the vaccinated group, however, it was not detectable, which clearly showed that the vaccine had prevented transmission of the virus from mother to fetus.