Richard T. Ellison III, MD reviewing Abbink P et al. Science 2016 Aug 4.

Three separate candidate Zika virus vaccines appear effective in preventing infection in rhesus monkeys.

Concern about the ongoing Zika virus (ZIKV) pandemic and about the associated risk for microcephaly for infants born to mothers infected during pregnancy has led to substantial efforts to produce a vaccine. A multinational team of researchers, who previously found evidence that both inactivated and DNA ZIKV vaccines could protect mice, have now extended studies of several candidate vaccines into nonhuman primate studies.

The researchers first immunized eight rhesus monkeys subcutaneously with two doses of a purified inactivated ZIKV vaccine (PIV). Compared with a sham vaccine, the PIV induced both detectable binding of antibodies to the ZIKV envelope and neutralizing antibodies, along with a cellular immune response. In challenge studies with both Brazilian and Puerto Rican ZIKV strains that induced disease in control monkeys, PIV-immunized monkeys had complete protection from infection (<100 virus copies/mL in blood, urine, cerebrospinal fluid, and colorectal or cervicovaginal secretions). In adoptive transfer studies, immunoglobulin G from ZIKV PIV–immunized monkeys protected both mice and monkeys from infection with ZIKV. Separately, a candidate ZIKV plasmid DNA vaccine induced neutralizing antibodies following a 4-week booster dose, and a rhesus adenovirus serotype 52 vector-based vaccine (RhAd52) induced neutralizing antibody by 2 weeks after the initial dose. All eight monkeys that received the DNA or RhAd52 vaccines showed complete protection from a subcutaneous challenge with a Brazilian ZIKV strain.

CITATION(S):

Abbink P et al. Protective efficacy of multiple vaccine platforms against Zika virus challenge in rhesus monkeys. Science 2016 Aug 4; [e-pub]. 

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