Testing of Zika Purified Inactivated Virus Vaccine Begins

Clinical trials to test the safety and efficacy of an investigational Zika vaccine—the Zika purified inactivated virus (ZPIV) vaccine—have begun at the Walter Reed Army Institute of Research (WRAIR) Clinical Trial Center in Silver Spring, Maryland, according to a news release from the National Institutes of Health (NIH).¹                              

The experimental ZPIV vaccine was created based on the technology WRAIR used to successfully develop a vaccine in 2009 for the Japanese encephalitis flavivirus. The ZPIV vaccine contains whole, inactivated Zika virus particles; however, “the protein shell of the inactivated virus remains intact so it can be recognized by the immune system and evoke an immune response,” according to the news release.

The study aims to enroll 75 people between the ages of 18 and 49 years with no prior flavivirus infection.  Participants will be randomly assigned into 3 groups: 25 will receive 2 intramuscular injections of the ZPIV test vaccine or a saline placebo 28 days apart; 25 will receive a 2-dose regimen of a Japanese encephalitis virus vaccine followed by the 2-dose ZPIV vaccine; and 25 will receive yellow fever vaccine before the 2-dose ZPIV vaccine. In addition, a subgroup of 30 participants will receive a third dose of the test vaccine one year later. “Investigators chose to administer additional flavivirus vaccines because US service members are often vaccinated against these diseases before deploying to Zika-endemic areas.”

“We urgently need a safe and effective vaccine to protect people from Zika virus infection as the virus continues to spread and cause serious public health consequences, particularly for pregnant women and their babies,” said Anthony S. Fauci, MD, director of the National Institute of Allergy and Infectious Diseases (NIAID).

Four additional phase 1 studies are scheduled to be launched in the coming months to evaluate the ZPIV investigational vaccine.  The studies will:

• Evaluate the optimal dose of the ZPIV vaccine for use in larger future studies;
• Assess the vaccine’s safety and immunogenicity in people already exposed to dengue virus;
• Test the ZPIV vaccine as a boost to the DNA Zika vaccine in development; and
• Examine a single dose of the ZPIV vaccine vs 2 doses at varying intervals.

WRAIR, NIAID, and the Biomedical Advanced Research and Development Authority (BARDA) have established a joint Research Collaboration Agreement to support the development of this vaccine. BARDA is funding the advanced development of the ZPIV vaccine candidate through a 6-year contract with Sanofi Pasteur.

Reference

1. Testing of investigational inactivated Zika vaccine in humans begins [news release]. Bethesda, MD: National Institutes of Health; November 7, 2016.