Singapore: Recently formed Liberia-US clinical research partnership sponsored by the National Institute of Allergy and Infectious Diseases (NIAID) has started a large clinical trial to assess the safety and efficacy of two experimental vaccines to prevent Ebola virus infection.

The Partnership for Research on Ebola Vaccines in Liberia or PREVAIL, a Phase 2/3 study, is designed to enroll approximately 27,000 healthy men and women aged 18 years and older.

Co-developed by NIAID scientists and GlaxoSmithKlineOne, vaccine candidate, cAd3-EBOZ, uses a chimpanzee-derived cold virus to deliver Ebola virus genetic material from the Zaire strain of virus causing the outbreak in Liberia.

The other candidate, VSV-ZEBOV, employs vesicular stomatitis virus, an animal virus that primarily affects cattle, to carry an Ebola virus gene segment. The VSV-ZEBOV vaccine was developed by the Public Health Agency of Canada and licensed to NewLink Genetics Corporation through its wholly owned subsidiary BioProtection Systems Corporation.

"The scale of the current Ebola outbreak in West Africa is unprecedented, and specific medical countermeasures are needed for this and future outbreaks," said Dr Anthony S Fauci, director, NIAID. "It is imperative that any potential countermeasures, including vaccines, be tested in a manner that conforms to the highest ethical and safety standards in clinical trials designed to provide a clear answer to the question of whether a candidate vaccine is safe and can prevent infection. This trial is designed to provide such answers."