By David S. Fedson, a retired professor of medicine at U.Va., and Steven M. Opal, a professor of medicine at Brown UniversityThis week, the World Health Organization endorsed the use of experimental drugs in the fight against the Ebola epidemic in West Africa. That is the right decision. There is no proven vaccine or treatment for Ebola, and in light of the severity of the current outbreak, experimental treatments that have not been tested on humans should be an option.