The woman overseeing the rush to develop an Ebola jab has become one of the first volunteers to sign up to test the safety of candidate vaccines being developed.

Marie-Paule Kieny, the World Health Organization's assistant director general for health systems and innovation, told Reuters that she signed up because it was the right thing to do.

"I've never been a guinea pig in any medical trials but the results of these clinical trials are absolutely crucial. We need to know if they are safe and we need to know which dose should be used," she said.

Kieny, a microbiologist who directed the WHO's vaccine research initiative for nine years, will not be at any risk of catching Ebola by trying out the vaccine.

The trials seek to determine not only whether the vaccine is safe or causes adverse side effects, but also whether it triggers the production of antibodies against the Ebola virus.

"You know, every month we have so many cases, so if I can do something myself or encourage others to volunteer, the clinical trial will be run as quickly as possible to have a response and be able to go to the next phase," she said.

The WHO has said there may be 10,000 new cases per week by December. At least 4,877 people are known to have died in the outbreak, the worst on record, but the true death toll is unknown and may be three times higher.

The two leading candidate vaccines, made by GlaxoSmithKline and NewLink Genetics, are being tested on volunteers in Britain, the United States and Mali and will soon begin safety trials in Switzerland, Germany, Gabon and Kenya.

Volunteers can be expected to be injected with the vaccine and then have regular checks on its effects on the body. Last month, early indications from the first batches of volunteers showed the GlaxoSmithKline vaccine raised "no red flags" in terms of adverse reactions.

Switzerland has not yet given final regulatory approval, but the trials have been approved by an ethics committee which means that state hospitals in Lausanne and Geneva can start screening volunteers, who need to be 18-65 years old and in good health.