WHO and DRC move to fast-track Phase 3 Ebola vaccine trial, starting with Merck’s Ervebo

The World Health Organization and authorities in the Democratic Republic of the Congo are negotiating to speed up the launch of a multi‑armed Phase 3 trial of Ebola vaccines.

The effort targets the Bundibugyo virus spreading in the country’s northeast, which WHO officials warned could become the largest Ebola outbreak on record.

Merck’s Ervebo, a vaccine that protects against Ebola Zaire, will be the first candidate deployed in the field. An expert panel that advises WHO was initially cautious, but growing animal‑study data has increased confidence.

The trial will assess safety and efficacy quickly to help contain the accelerating epidemic, reflecting the urgent public‑health need.