An international team from the National Institute of Allergy and Infectious Diseases (NIAID) is testing an experimental Zika vaccine. For the time being, the vaccine has proven effective on macaques used as animal models.

The vaccine reduced the virus levels in pregnant monkeys, improving the health conditions of the young. Now scientists are evaluating Phase 2 of the trial, the one on humans. The vaccine uses a small piece of DNA, inside which there are genes encoding the proteins present on the surface of the Zika virus. In this way they induce a response by the host's immune system, which manages to counteract the devastating effects of the virus on fetuses.

According to the authors, this would be enough to avoid the transmission of the virus and the consequences on development. To prove the effectiveness of the system, scientists compared 12 unvaccinated and 13 vaccinated guinea pigs before gestation. All guinea pigs were exposed to the Zika virus three times during the first and second trimester. Vaccinated animals showed far fewer traces of the virus in the blood.

Most importantly, the vaccine appears to have reduced the chances of passing the virus on to the fetus. None of the 13 children in the second group showed congenital defects. If the vaccine also proved effective on humans, it could be used to counter the epidemic raging in South America. Scientists suggest administration to adolescents and adults of childbearing age, so as to immunize them before any gestation.

Source: nih.gov