Merck, (known as MSD outside the U.S. and Canada), has announced its investigational Ebola vaccine candidate, rVSV-ZEBOV, was found to have 100% efficacy in an analysis of interim data from a phase III ring vaccination trial in Guinea. Preliminary conclusions from this study, which is continuing, were published online in The Lancet. The authors report that vaccine efficacy was 100% (95% confidence interval: 74.7 - 100%; p=0.0036) following vaccination with a single dose of the rVSV-ZEBOV vaccine. It appeared that all vaccinated individuals were protected against Ebola virus infection within six to 10 days of vaccination.

To date, more than 4,000 participants have received the vaccine in this innovative trial, called “Ebola ça suffit” or “Ebola, that’s enough.” The trial was conducted by a team that included researchers from the World Health Organization (WHO), the Norwegian Institute of Public Health, the Health Ministry of Guinea and Médecins sans Frontières, among others. The results from this continuing study, as well as other studies already under way and additional studies to be conducted, will be used to support worldwide regulatory submissions.

“Merck has an enduring commitment to develop vaccines and medicines that address the world’s most devastating infectious diseases,” said Dr. Roger M. Perlmutter, president of Merck Research Laboratories. “Building on pioneering early work by the Public Health Agency of Canada and NewLink Genetics, the extraordinary efforts of the team in Guinea and other experts have yielded interim results that suggest a potential role for our rVSV-ZEBOV vaccine in the fight against Ebola disease.”

In addition to NewLink and the Public Health Agency of Canada, global and national health organizations including the National Institute of Allergy and Infectious Diseases (NIAID), the Walter Reed Army Institute of Research (WRAIR), the Canadian Immunization Research Network (CIRN) and the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) have helped to conduct studies of the rVSV-ZEBOV vaccine.

Major funders for these studies included the U.S. Department of Defense’s Defense Threat Reduction Agency (DTRA) and Joint Vaccine Acquisition Program (JVAP), the U.S. Department of Health and Human Service’s Biomedical Advanced Research Development Authority (BARDA), the National Institutes of Health and the Wellcome Trust.