NIAID is developing multiple vaccine candidates to prevent Zika virus infection. These include:
- A DNA-based vaccine developed by scientists at NIAID’s Vaccine Research Center (VRC). The strategy is similar to the VRC’s investigational flavivirus vaccine for West Nile virus infection, which was found to be safe and induced an immune response in a Phase 1 clinical trial. The DNA-based Zika vaccine candidate entered a Phase 1 clinical trial at NIAID in August 2016. A second Phase 1 trial testing an optimized vaccine design launched in December 2016, and initial immunogenicity results are expected in early spring 2017. NIAID plans to launch a Phase 2/2b trial in March 2017. The trial aims to enroll 2400-5000 participants across approximately 30 sites. NIAID is working closely with CDC to identify sites in the U.S., the Caribbean, and Central and South America likely to see high Zika incidence. The Phase 2/2b trial will further evaluate the safety and immunogenicity of the vaccine and aims to determine if the vaccine can effectively prevent Zika virus infection.
- A purified inactivated Zika vaccine called ZPIV, developed by the Walter Reed Army Institute of Research (WRAIR). ZPIV is based on a similar approach that WRAIR used to develop vaccines against the related Japanese Encephalitis and dengue viruses. Three of five Phase 1 trials testing ZPIV have begun at the Walter Reed Army Institute of Research (WRAIR) Clinical Trial Center in Silver Spring, Maryland; the Center for Vaccine Development at the Saint Louis University School of Medicine; and the Center for Virology and Vaccine Research, part of Beth Israel Deaconess Medical Center and Harvard Medical School in Boston. The clinical research center CAIMED, part of Ponce Health Sciences University in Puerto Rico will also evaluate ZPIV in a Phase 1 trial. NIAID is co-funding the Phase 1 clinical trials program with WRAIR, serving as the regulatory sponsor for several of these clinical studies and providing other support. NIAID’s VRC will also test ZPIV as a boost to its DNA Zika vaccine candidate.
- A live-attenuated (in which the virus has been weakened so that it cannot cause disease) investigational vaccine designed to protect against Zika virus and dengue virus infection. Scientists in NIAID’s Laboratory of Infectious Diseases developed the vaccine, which is closely related to a dengue vaccine candidate currently being evaluated in a large Phase 3 study in Brazil. A monovalent version of the vaccine that is designed to protect against solely Zika virus will enter a Phase 1 trial in March 2017 at Johns Hopkins University in Baltimore and University of Vermont. Another version of the vaccine designed to protect against Zika and all four types of dengue will enter clinical testing in May 2017. NIAID is working with Brazil’s Butantan Institute and the University of Sao Paolo to plan later-stage trials.
- Several investigational mRNA vaccines (a gene-based platform similar to DNA vaccines). NIAID’s VRC is working with GlaxoSmithKline (GSK), University of Pennsylvania and Moderna/Valera to evaluate various mRNA vaccine technologies to identify immunogenic and scalable candidates. The Moderna/Valera candidate is being evaluated in a Phase 1 trial, and the candidate developed by NIAID VRC and GSK could enter clinical trials in late 2017.
- An investigational Zika vaccine that uses a genetically engineered version of vesicular stomatitis virus—an animal virus that primarily affects cattle. VSV was successfully used in an investigational Ebola vaccine tested by NIAID. This vaccine approach is at an early stage with plans underway to evaluate the Zika vaccine candidate in tissue culture and animal models.
Early-stage trials examine whether an experimental vaccine is safe and generates immune responses in vaccinated volunteers. A safe and effective, fully licensed Zika vaccine will likely not be available for several years.