Final test results confirm experimental Ebola vaccine highly effective

Final test results confirm an experimental Ebola vaccine is highly effective, a major milestone that could help prevent the spread of outbreaks like the one that killed thousands in West Africa.

Scientists have struggled to develop an Ebola vaccine over the years, and this is the first one proven to work. Efforts were ramped up after the infectious disease caused a major outbreak, beginning in 2013 in Guinea and spreading to Liberia and Sierra Leone. About 11,300 people died.

The World Health Organization, which acknowledged shortcomings in its response to the West Africa outbreak, led the study of the vaccine, which was developed by the Canadian government and is now licensed to the U.S.-based Merck & Co. Results were published Thursday.