WASHINGTON (AP) — Federal researchers next week will start testing humans with an experimental vaccine to prevent the deadly Ebola virus.

The National Institutes of Health announced Thursday that it is launching the safety trial on a vaccine developed by the agency’s National Institute of Allergy and Infectious Diseases and GlaxoSmithKline. Beginning Tuesday, it will test 20 healthy adult volunteers to see if the virus is safe and triggers an adequate response in their immune systems.