Three different investigational Zika virus vaccine platforms--an inactivated virus vaccine, a DNA-based vaccine, and an adenovirus vector-based vaccine--protected against infection, induced immune responses, and produced no adverse side effects when tested in rhesus macaques challenged with the Zika virus, according to findings appearing August 4 in the journal Science. The results suggest that each of the three approaches holds promise for designing an effective Zika vaccine, according to the authors.
Researchers supported by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, first tested the inactivated Zika virus vaccine in 16 rhesus macaques, with eight receiving the experimental vaccine and eight receiving a placebo injection. Within two weeks after the initial injection, all vaccinated animals developed neutralizing antibodies as well as antibodies specific to the viral envelope protein, a key vaccine target on the Zika virus. A second dose was given four weeks later, which substantially boosted antibody levels. The monkeys were then challenged with Zika virus; following exposure, the vaccinated animals had no detectable virus and showed no other evidence of infection, while the group that received the placebo injection developed high levels of virus replication in the blood and other tissues for six to seven days.
In another experiment, the researchers administered two doses of an experimental DNA vaccine, one dose of an experimental adenovirus vector vaccine, or a placebo injection to three groups of four monkeys each. The group that received the DNA vaccine received a booster shot four weeks after the initial vaccination. Minimal levels of antibodies were detected after the first injection. However, after the second injection, researchers detected Zika-specific neutralizing antibodies in the animals. The adenovirus vector-based vaccine induced Zika-specific neutralizing antibodies two weeks after the single injection. Monkeys were exposed to Zika virus four weeks after the final vaccination, and both the DNA and adenovirus vector vaccine provided complete protection against infection. These encouraging findings suggest a path forward for clinical development of Zika vaccines in humans, according to the researchers.
P Abbink et al. Protective efficacy of multiple platforms against Zika virus challenge in rhesus monkeys. Science DOI: 10.1126/science.aah6157 (2016).
NIAID Director Anthony S. Fauci, M.D. is available for comment.
To schedule interviews, please contact Emily Mullin, (301) 402-1663, firstname.lastname@example.org.
NIAID conducts and supports research--at NIH, throughout the United States, and worldwide--to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID website.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.