WASHINGTON, July 31 (UPI) -- A vaccine for the Ebola virus has shown 100 percent efficacy in the midst of a Phase III clinical trial in Guinea, researchers with the World Health Organization announced today.
The trial for the vaccine, called VSV-EBOV, in Guinea began in March using a "ring vaccination" method, which involves vaccinating all of the people who have come in contact with an infected person, creating a protective ring of non-infection around the person.
After seeing the results of the trial thus far, the international Data and Safety Monitoring Board and Guinean national regulatory authority and ethics review committee have approved continuing, and expanding, the study.
"The 'ring' vaccination method adopted for the vaccine trial is based on the smallpox eradication strategy," said John-Arne Røttingen, Director of the Division of Infectious Disease Control at the Norwegian Institute of Public Health, in a press release. "The premise is that by vaccinating all people who have come into contact with an infected person you create a protective 'ring' and stop the virus from spreading further. This strategy has helped us to follow the dispersed epidemic in Guinea, and will provide a way to continue this as a public health intervention in trial mode."
Starting on March 23, researchers identified 100 Ebola patients and began vaccinating more than 4,000 family members, neighbours, and co-workers who they interact with. Initially, the trial involved randomizing who received the vaccine, with about 50 percent of people around patients being vaccinated.
On July 26, as a result of successfully slowing or stopping the spread of Ebola within communities where people had been effected, researchers stopped randomizing the vaccinations and began giving it to everyone.
"It is certainly promising," Marie-Paule Kieny, an assistant general director general at the World Health Organization, told BBC News. "Prior to vaccination there were cases, cases, cases. The vaccine arrives and 10 days later the cases are flat. It could be a game-changer because previously there was nothing, despite the disease being identified 40 years ago. When there is a new outbreak this vaccine will be put to use to stop the outbreak as soon as possible to not have the terrible disaster we have now."
Results of the clinical trial thus far are published in The Lancet.