Two Ebola Vaccine Candidates Recommended for Congo Trial

Two more candidates for a trial

November 7, 2026 · 5:00 a.m. Central

World Health Organization advisers have recommended adding two experimental vaccines to a clinical trial in the Democratic Republic of the Congo as health workers respond to an outbreak of Ebola disease caused by the Bundibugyo virus.

The candidates, developed by Oxford University with the Serum Institute of India and by Moderna, would join the existing Tumaini trial after national approvals, WHO said. The recommendation is a step toward testing, not proof that either vaccine works or is approved for routine use.

The first participants in the trial enrolled in Bunia on October 23, according to a WHO outbreak update. A separate vaccine already in the study is licensed for a different Ebola virus; researchers are evaluating whether it protects against Bundibugyo.

How the research works

The two Bundibugyo-specific candidates are ChAdOx1 BDBV and mRNA-1469. WHO’s independent advisory group recommended their inclusion based on available early clinical and preclinical evidence, as detailed in its meeting report.

Tumaini uses a “ring” approach: it enrolls contacts of people with confirmed infections to study vaccine candidates during an outbreak. WHO said four vaccination rings were in place as of its November 4 announcement. That number may have changed.

The trial is designed to produce evidence about protection and safety. WHO said results were expected in early 2027; a forecast is not a guarantee of when results or authorization will arrive.

The outbreak and the response

As of November 3, Congo had reported 10,668 confirmed cases and 5,198 deaths among confirmed cases, WHO said in its November 6 update. Those figures reflect reporting through that date, and the organization said transmission remained widespread.

No vaccine or specific treatment is approved for Bundibugyo virus disease, WHO said. The response also relies on rapid diagnosis, care, contact tracing, infection prevention, safe burials and community engagement. Separate treatment studies are ongoing.

Anadolu Agency also reported the planned additions. The candidates remain investigational, and access and national authorization will depend on the trial and local authorities.

Key dates

• May 2026: Congo declared the outbreak.
• October 23: The Tumaini trial launched and its first participants enrolled in Bunia, WHO said.
• November 4: WHO announced the recommendation to add two candidates after national approvals.
• November 6: WHO published an outbreak update using data through November 3.

Where the trial began

The star marks the approximate Bunia, Democratic Republic of the Congo area, not a precise event location.

WHO’s post on the response

In a November 4 post, WHO described the human toll and its work with partners on vaccines and treatments. The post reflects the organization’s own update, not independent evidence of vaccine effectiveness.

Read WHO’s post

Open the original post if the embed does not load.

Sources and visual credits

WHO vaccine announcement · WHO outbreak update · WHO advisory report · Anadolu Agency · WHO on X.

Hero and thumbnail: conceptual illustration, not a photograph of the trial. Map data: OpenStreetMap contributors, ODbL.