An experimental vaccine against the deadly Ebola virus has provoked only mild side effects in volunteers in Switzerland, claims Geneva hospital.
"To date, no major side effects have been observed after the injections," the Geneva University Hospital (HUG) said in a statement.
The hospital is one of several worldwide hosting trials of the experimental VSV-ZEBOV Ebola vaccine, manufactured by the Public Health Agency of Canada and licenced by US firm NewLink Genetics.
It said 34 of the 115 volunteers taking part in the clinical trial had already received injections with either VSV-ZEBOV or with a placebo.
"Observations and initial analysis showed that vaccinated volunteers responded with an inflammatory reaction, precisely as expected," HUG said.
"These lasted from a few hours to two to three days, with mild fever in certain cases and no major side effects," it added.
The clinical trial will continue into early 2015, with around 15 volunteers receiving an injection each week.
There is no licensed treatment or vaccine for Ebola and the World Health Organization has endorsed rushing potential ones through trials in a bid to stem the epidemic, raging mainly in Guinea, Liberia and Sierra Leone.
Some 6,000 people have died so far in the outbreak that began less than a year ago.
The VSV-ZEBOV vaccine is also being tested on volunteers in the United States, Canada, Germany and Gabon, and clinical trials are also due to start soon in Kenya.
HUG said it was seeking volunteers who will be travelling to the west African countries most affected by the Ebola outbreak.
"These volunteers will not receive a placebo for ethical reasons," it said.
Another Swiss hospital, the CHUV in Lausanne, is also conducting trials of another experimental vaccine, made by Britain's GlaxoSmithKine.
Trials of that vaccine are also underway in Mali, Britain and the United States.