A purified inactivated vaccine derived from Vero cell-adapted zika virus elicits protection in mice.

The Zika virus (ZIKV) outbreak in 2015-2016 raised public health concerns and created a pressing need for vaccine development. However, no vaccine has been developed and most of the ones under development use a single serotype of ZIKV. In this study, we established a Vero cell-adapted ZIKV strain (GMZ-002) and developed a purified inactivated virus (PIV) vaccine. GMZ-002 presented significantly increased productivity in Vero cells, and IFNAR1-blocked C57BL/6 mice administered two doses of the PIV were fully protected against lethal challenge. Vaccine efficacy was illustrated by the high level of serum neutralizing antibodies and strong innate immune response, along with an absence of detectable viremia in vaccinated mice. Furthermore, anti-sera neutralized both African and Asian genetic lineages of the virus in vitro. Our results suggest that GMZ-002 PIV elicited robust and persistent protective immunity, and therefore represents a promising vaccine candidate for ZIKV.