Liberia Ebola vaccine trial "challenging" as cases tumble
By Ben Hirschler DAVOS, Switzerland (Reuters) – A steep fall in Ebola cases in Liberia will make it hard to prove whether experimental vaccines work in a major clinical trial about to start in the country, the head of the U.S. National Institutes of Health (NIH) said on Saturday. The NIH might have to move some testing to neighbouring Sierra Leone, while regulators could end up approving Ebola shots based on efficacy data from animal tests backed by only limited human evidence, Francis Collins told Reuters. Liberia, once the epicentre of West Africa's deadly Ebola epidemic, has just five remaining confirmed cases of the disease, a senior health official has said.
