It was developed by the Public Health Agency of Canada, with development subsequently taken over by Merck Inc.[12] In October 2014, the Wellcome Trust, who was also one of the biggest UK founders,[13] announced the start of multiple trials in healthy volunteers in Europe, Gabon, Kenya, and the US.[14] The vaccine was proven safe at multiple sites in North America, Europe, and Africa, but several volunteers at one trial site in Geneva, Switzerland, developed vaccine-related arthritis after about two weeks, and about 20–30% of volunteers at reporting sites developed low-grade post-vaccine fever, which resolved within a day or two.