Updated

Swiss researchers have suspended the testing of one of the leading Ebola vaccine candidates after some volunteers reported unexpected side effects.

In a statement issued on Thursday, the Hopitaux Universitaires de Geneve said the trial had been suspended "as a precautionary measure." The study involving 59 people began in November.

Researchers reported four cases of mild joint pain in the hands and feet in people who got the shot 10 to 15 days earlier. Officials will stop giving the vaccine next week to get more data and liaise with others who are testing the vaccine in the U.S., Canada, Germany and Gabon.

The vaccine was developed by the Canadian government and is licensed to two U.S. companies, NewLink and Merck

The trial is scheduled to resume in January in Geneva.