The Swiss agency that regulates new drugs said Tuesday it has approved an application for a clinical trial with an experimental Ebola vaccine at the Lausanne University Hospital.

Swissmedic said the trial will be conducted among 120 volunteer participants with support from the U.N. World Health Organization. The experimental vaccine is to be initially administered on healthy volunteers who will be sent as medical staff to fight the Ebola epidemic in West Africa.

In a statement, the Bern-based Swiss government agency said the trial continues a series that began in the United States, Britain and Mali, using a vaccine based on a genetically modified chimpanzee adenovirus.

There are no proven drugs or vaccines for Ebola, mainly because the disease is so rare it's been hard to attract research funding. But with governments and businesses now rapidly shifting millions of dollars to fight the Ebola epidemic centered in West Africa, WHO says two leading candidates for a vaccine have emerged.

One of them — now approved by Swissmedic for a trial — is a vaccine co-developed by the U.S. National Institutes of Health and GlaxoSmithKline, which was funded by the company, its charitable trust and funds from the U.S. and U.K. governments. GSK has said it might be able to make about 1 million doses of its vaccine per month by the end of 2015.

The other front-runner vaccine is licensed by a small U.S. drugmaker, NewLink Genetics, and was initially developed by the Public Health Agency of Canada. It has been sent to the U.S. Walter Reed Army Institute of Research for testing on healthy volunteers, with preliminary safety results expected by December.