A newly developed vaccine against the deadly Ebola virus is “highly effective” and could help prevent its spread in the current and future outbreaks, the World Health Organization said Friday.
Trials of the VSV-EBOV vaccine began in March in Guinea — one of three West African nations at the center of the outbreak — and have shown such promise that this week it was decided to extend immediate vaccination to “all people at risk,” a WHO news release said.
“This is an extremely promising development,” said Dr. Margaret Chan, the body’s director general.
“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.”
More research is needed, but the results so far on this trial show 100% efficacy.
It will take weeks at the least, and possibly a couple of months, for more supply to be made, according to Chan.
Until this week, researchers were using a “ring” strategy — based on that used in smallpox eradication — to trial the vaccine’s effectiveness.
“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,” said John-Arne Rottingen, of the Norwegian Institute of Public Health, which has been involved in implementing the trial.
To date, more than 4,000 close contacts of almost 100 Ebola patients, including family members, neighbors and co-workers, have voluntarily participated in the trial, the WHO news release said.
“The trial stopped randomisation on 26 July to allow for all people at risk to receive the vaccine immediately, and to minimize the time necessary to gather more conclusive evidence needed for eventual licensure of the product.”
The trial will now include 13- to 17-year-olds, and possibly children from the age of 6, on the basis of new evidence of the vaccine’s safety, it added.
The vaccine is also being trialled by front-line health workers, said Medecins sans Frontieres, also known as Doctors without Borders.
The VSV-EBOV vaccine was developed by the Public Health Agency of Canada and licensed to Merck and NewLink.
The Guinea trial is being implemented by the Guinean authorities, the WHO, MSF and the Norwegian Institute of Public Health, with support from a range of international and national organizations.
The concerted effort to find a vaccine reflects the severity of the crisis posed by Ebola, spread through contact with body fluids from an infected person or contaminated objects from infected persons. Other vaccines are also being trialled.
More than 10,000 people have died in the three worst-affected countries — Guinea, Sierra Leone and Liberia — since the epidemic took hold last year.
In May, officials from the WHO declared Liberia free of the disease. But even as they trumpeted the news, officials warned that outbreaks in Guinea and Sierra Leone ran the risk of bringing the virus back to Liberia, where more than 4,000 people died after contracting Ebola. A 17-year-old in Nidonwin, Liberia, subsequently died of the disease.