Zika Vaccine Is Well Tolerated, Effective

An investigational whole inactivated Zika virus vaccine was well tolerated and protective in healthy adults, according to the results of a preliminary study.

“Zika virus has the potential to be like other viruses that are dangerous in pregnancy—think measles, mumps or rubella—that were knocked down significantly by effective vaccines,” said co-lead author Kathryn Stephenson, MD, MPH.
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The researchers conducted 3 phase 1, placebo-controlled, double-blind trials of a purified formalin-inactivated Zika virus vaccine (ZPIV) candidate that had previously shown protection in mouse and non-human studies. Overall, 67 healthy adults were enrolled in the studies and randomly assigned to receive 5 μg ZPIV or saline placebo in a 4:1 ratio. Vaccinations were given on days 1 and 29.

Only mild-to-moderate adverse events were reported, the most frequent of which were pain or tenderness at the injection site, as well as fatigue, headache, and malaise. At day 57, 52 (92%) of the vaccine recipients had seroconverted, with peak geometric mean titres observed at day 43 and exceeding protective thresholds seen in animal studies.

“The ZPIV candidate was well tolerated and elicited robust neutralising antibody titres in healthy adults.”

—Michael Potts

Reference:

Modjarrad K, Lin L, George SL, et al. Preliminary aggregate safety and immunogenicity results from three trials of a purified inactivated Zika virus vaccine candidate: phase 1, randomised, double-blind, placebo-controlled clinical trials [published online December 2017]. Lancet. doi: http://dx.doi.org/10.1016/S0140-6736(17)33106-9.