The trial comes amid a worsening Ebola crisis that has claimed more than 4,600 lives in the DRC since May. Despite the scale of the outbreak, no vaccine has yet been approved specifically against the Bundibugyo virus.

A major clinical trial to evaluate vaccines against the Bundibugyo Ebola virus began Friday in the eastern Democratic Republic of the Congo (DRC), with the first participants vaccinated as the country battles the largest recorded outbreak of the virus.

The Phase 2/3 trial, known as Tumaini, was launched in Bunia, the capital of the hardest-hit Ituri Province, said the Coalition for Epidemic Preparedness Innovations, which is funding and supporting the study.