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Zika Studies

The Walter Reed Army Institute of Research (WRAIR) has been studying infectious diseases including flaviviruses for more than 100 years. By leveraging its international research infrastructure and extensive infectious disease expertise, WRAIR was able to respond quickly to the Zika threat by developing a promising preventive vaccine.

Working in concert with government, industry and academic collaborators, WRAIR has developed a Zika Purified Inactivated Virus (ZPIV) vaccine candidate. Researchers were able to move from initial conceptualizing of a Zika vaccine to publishing preclinical findings in two high impact publications within an unprecedented 180 days.

Institute researchers decided to move forward with the purified inactivated virus vaccine because it builds on a type of vaccine that has been licensed before. It is the same technology WRAIR used to develop its Japanese encephalitis vaccine, which was licensed in 2009.

Promising Preclinical Findings

In June 2016 WRAIR and collaborators at Harvard University completed a promising preclinical study of the ZPIV vaccine, the findings of which were published in the journal Nature and demonstrated that single shots of the vaccine protected mice against subsequent Zika challenge.

Findings from another preclinical study in rhesus monkeys showed that the ZPIV candidate induced both binding and neutralizing antibodies in the two weeks after initial vaccination, which were substantially boosted following a second ZPIV dose given at week four. After being experimentally infected with Zika virus, vaccinated monkeys showed complete protection against both Brazilian and Puerto Rican strains of Zika virus as evidenced by no detectable virus in blood, urine and secretions after exposure. The study was published in the journal Science in August 2016.

Next Steps

WRAIR scientists are moving rapidly to develop and test the ZPIV vaccine, and they plan to start human testing at their clinic in Silver Spring before the end of 2016. Additional human trials are planned in the United States, supported by the National Institute of Allergy and Infectious Diseases (NIAID), through its Vaccine and Treatment Evaluation Units.

The Army has signed a Cooperative Research and Development Agreement with Sanofi Pasteur, transferring the ZPIV technology to Sanofi to explore advanced and larger scale manufacturing and production. In September, Biomedical Advanced Research and Development Authority (BARDA) announced they will fund $43.2 million to Sanofi Pasteur to support the advanced development of ZPIV.

Foundation of Flavivirus Research

WRAIR has been researching flaviviruses, a family of viruses that includes yellow fever, Japanese encephalitis, dengue, West Nile and Zika viruses, for over a century, beginning in the 1890s when Major Walter Reed helped prove that yellow fever is spread by the Aedes aegypti mosquito.

A laboratory in Thailand has been conducting biosurveillance for Zika for the past three years, an effort that gave the Institute a head-start on vaccine development efforts. WRAIR also has in-house capabilities that have enabled them to quickly develop a vaccine candidate. The Pilot Bioproduction Facility headed by Dr. Kenneth H. Eckels produced small batches of vaccine candidates that were used for the preclinical studies and has manufactured a vaccine lot for use in initial human clinical studies.