Ebola Vaccine Shows 100% Efficacy in Phase III Trial

The World Health Organization reported that results from an interim analysis of a Phase III trial conducted in Guinea show the Ebola vaccine VSV-EBOV is highly effective against the virus. The vaccine was given to subjects who had been in close contact with an infected individual. Preliminary results, published in The Lancet, showed 100% efficacy of the vaccine.

The Data and Safety Monitoring Board has advised that the trial should continue, as more conclusive evidence is needed. The Guinean national regulatory authority and ethics review committee have approved continuation of the trial.

"This is an extremely promising development," said Dr Margaret Chan, director-general of WHO, in a press statement. "The credit goes to the Guinean Government, the people living in the communities, and our partners in this project. An effective vaccine will be another very important tool for both current and future Ebola outbreaks."

The Guinea vaccination trial was started on March 23, 2015 to evaluate the efficacy and safety of a single dose of the vaccine VSV-EBOV in affected communities. A ring vaccination protocol was used in this trial, in which case, those in close contact with an infected person were vaccinated to prevent spread of the virus. Some of the rings are vaccinated shortly after a case is detected, and other rings are vaccinated after three weeks. More than 4000 subjects have voluntarily participated in this trial to date.  

VSV-EBOV was developed by the Public Health Agency of Canada. The vaccine was licensed to NewLink Genetics, and on November 25, 2014, Merck and NewLink Genetics entered into an exclusive worldwide licensing agreement wherein Merck assumed responsibility to research, develop, manufacture, and distribute the investigational vaccine. Financial support was provided by the Canadian and US governments, among others.

Source: WHO