Experimental Ebola Vaccine Safe, Prompts Immune Response

An early-stage clinical trial of an experimental Ebola vaccine conducted at the National Institutes of Health and the Walter Reed Army Institute of Research (WRAIR) found that the vaccine, called VSV-ZEBOV, was safe and elicited robust antibody responses in all 40 of the healthy adults who received it. The most common side effects were injection site pain and transient fever that appeared and resolved within 12–36 hours after vaccination. A report describing preliminary results of the NIH-WRAIR study appears online in The New England Journal of Medicine. The VSV-ZEBOV candidate is one of two experimental Ebola vaccines now being tested in the phase II/III PREVAIL clinical trial that is enrolling volunteers in Liberia.

“The ongoing Ebola ongoing outbreak in West Africa is unprecedented in scope and duration,” said Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases (NIAID), part of NIH. “The outbreak is slowly coming under control, thanks to extraordinary and multi-faceted efforts in the affected nations. However, there still are no licensed specific therapies or vaccines for Ebola. Until a safe and effective vaccine is available, the world will continue to be under-prepared for the next Ebola outbreak.”

Scientists at the Public Health Agency of Canada developed the candidate vaccine. It was licensed to NewLink Genetics Corp. of Ames, Iowa, a company collaborating with Merck & Co. Inc., of Kenilworth, New Jersey, which is responsible for advancing this vaccine towards regulatory approval. The investigational vaccine is based on a genetically modified and attenuated vesicular stomatitis virus (VSV), a virus that mainly affects cattle. In the investigational vaccine, a gene for a VSV protein is replaced with a gene segment from a key protein in the Zaire species of Ebola virus. The vaccine does not contain the whole Ebola virus and therefore cannot infect vaccinated persons with Ebola.

“The prompt, dose-dependent production of high levels of antibodies following a single injection and the overall favorable safety profile of this vaccine make VSV-ZEBOV a promising candidate that might be particularly useful in outbreak interventions,” said Dr Davey.