Scientists coming closer to Zika Vaccine

Washington D.C : A team of Sc may be a step closer to developing some protection from Zika virus (ZIKV) with multiple vaccines in the works.

Researchers at Beth Israel Deaconess Medical Center (BIDMC), Walter Reed Army Institute of Research (WRAIR) and the University of Sao Paulo demonstrated that two different ZIKV vaccine candidates provided complete protection in mice against a ZIKV strain from Brazil and suggest that a ZIKV vaccine for humans will likely be feasible.

"Our data demonstrate that a single dose of a DNA vaccine or a purified inactivated virus vaccine provides complete protection against the ZIKV challenge in mice," said senior author Dan H. Barouch, adding "Importantly, we showed that vaccine-induced antibodies provided protection, similar to existing vaccines for other flaviviruses."

The researchers tested two vaccine candidates: a DNA vaccine developed in the Barouch laboratory at BIDMC, and a purified inactivated virus vaccine developed at WRAIR. The DNA vaccine used gene sequences from a ZIKV strain from Brazil to elicit immune responses.

Four weeks following vaccination, mice were exposed to the Brazilian strain of ZIKV, which had previously been shown to cause defects in fetal mice similar to those observed in ZIKV infected humans. All vaccinated mice were protected from ZIKV replication. Other mice were vaccinated and exposed to infection eight weeks later and were also protected from infection.

Barouch noted that the effectiveness of these vaccines, the clarity of the antibody protection and the similarity to successful vaccines that have been developed for other flavi-viruses provide substantial optimism for a clear path forward for the development of a safe and effective ZIKV vaccine for humans.

Clinical trials to test these vaccine candidates are expected to begin later this year.

The study is published in the journal Nature.