Ebola/Marburg Vaccine Development
Building on their previous results showing that a heterologous prime-boost vaccination strategy produced strong, long-lasting immune responses in vaccinated non-human primates, scientists at the Vaccine Research Center (VRC), in collaboration with researchers at the US Army Medical Research Institute for Infectious Disease (USAMRIID), developed an accelerated Ebola vaccine. The scientists tested whether the immune response mounted against the boost component alone would be sufficient to protect monkeys against Ebola infection. They discovered that monkeys vaccinated with only the boost survived, even those who received high doses of Ebola virus.
In October 2005, the VRC completed a study of the first human trial of a DNA vaccine designed to prevent Ebola infection. The trial was comprised of three vaccinations given over three months, and study participants were followed for one year. Results show that this DNA vaccine was safe and well tolerated with no significant adverse events, and it was capable of inducing an immune response.
Based on previous studies showing protection in monkeys, VRC scientists have recently developed a fast-acting, single shot experimental Ebola vaccine for humans. A Phase I adenovirus vaccine trial in humans began in September 2006 and was completed in October 2008. If this vaccine platform proves effective, it could one day be used to quickly contain Ebola outbreaks with ring vaccination—the same strategy used in the past against smallpox. The ring vaccination strategy, which requires a fast-acting vaccine, not only protects people who may have been exposed to Ebola but also creates an added barrier of immunity around them, thereby protecting the entire community.
The VRC is evaluating a new Ebola DNA vaccine and Marburg DNA vaccine in Phase I and Ib studies. These studies are testing the safety and immunogenicity of candidate vaccines expressing the immunogen wild type glycoprotein. Based on non-human primate studies, wild-type glycoprotein antigen induces that most protective immune response against an otherwise lethal Ebola virus challenge, and represents the third generation of antigens being evaluated in clinical research studies of candidate filovirus vaccines at the VRC. In 2009, expanded clinical trials are being conducted in collaboration with the Walter Reed Army Institute of Research (WRAIR) US Military HIV Research Program, Makerere University Walter Reed Project (MUWRP) in Kampala Uganda, and the Infectious Diseases Clinical Research Program (IDCRP) of the Uniformed Services University, Bethesda Maryland.
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