Early-stage trials of an experimental Ebola vaccine indicate it is safe and triggers antibodies. There is currently no vaccine for the virus that has killed thousands in West Africa.
Without a licensed treatment or vaccine for Ebola, the World Health Organization (WHO) last year endorsed a fast-track process for potential treatments through trials. The latest, and worst outbreak of Ebola has killed more than 10,000 people in West Africa.
Initial clinical trials of the VSV-ZEBOV candidate vaccine, manufactured by the Public Health Agency of Canada and developed by Merck, show that it "triggers the production of antibodies capable of neutralising the Ebola virus," the Geneva University Hospitals (HUG) said in a statement on Wednesday.
In coordinated trials in Germany, Switzerland, Gabon and Kenya, 158 healthy volunteers received a placebo or any of five dose-levels of VSV-ZEBOV vaccine. All 150 people who received vaccine developed antibodies to Ebola and higher responses were related to higher doses.
Reports of the trials published in the New England Journal of Medicine indicated that even very small amounts of the vaccine could be effective. The phase 1 trials are aimed at testing for safety.
Follow-up analysis six and 12 months later should determine "whether a single injection is enough to induce a lasting immune response" or if booster injections would be needed, HUG said.
The HUG statement emphasized that phase 3 clinical trials being carried out in Guinea "will determine whether the immune response triggered by this vaccine is able to protect the population against the Ebola virus." They should also show if large-scale vaccination campaigns are feasible.
The trials at HUG were briefly suspended late last year after several volunteers experienced unexpected joint pains, but resumed after it reduced the doses used.
There were also trials carried out in the United States, at the National Institutes of Health and the Walter Reed Army Institute of Research. They began last October and involved 52 volunteers.
Another experimental vaccine, ChAd3, made by Britain's GlaxoSmithKline is also undergoing phase 1 trials in a range of countries and started phase 3 trials in Liberia in February.
jm/sms (Reuters, AFP)