U.s. National Institute Of Allergy

A large-scale human trial of two potential Ebola vaccines got under way in Liberia's capital Monday, part of a global effort to prevent a repeat of the epidemic that has now claimed nearly 9,000 lives in West Africa.

A large-scale human trial of two potential Ebola vaccines got under way in Liberia's capital Monday, part of a global effort to prevent a repeat of the epidemic that has now claimed nearly 9,000 lives in West Africa.