WHO Adds Two Ebola Vaccine Candidates to DRC Bundibugyo Trial

Expert groups convened by the World Health Organization (WHO) have recommended adding two new Ebola vaccine candidates to the ongoing Tumaini clinical trial in the Democratic Republic of the Congo (DRC). It is the first time vaccines designed specifically against Bundibugyo virus - the virus responsible for the current outbreak - will be evaluated during an outbreak of the disease.

The two candidates are ChAdOx1, developed by the University of Oxford with the Serum Institute of India, and Moderna's mRNA-1469. WHO's independent Technical Advisory Group on Candidate Vaccines Prioritization recommended both for further clinical evaluation this week on the basis of available preclinical and early clinical evidence. The companies were informed on Monday, and the candidates will enter the trial following national approvals.

"The fact that these vaccines are ready to enter clinical trials is a testament to the power of science and partnership," said Dr Tedros Adhanom Ghebreyesus, WHO Director-General. "Vaccines alone will not end this outbreak, but they could become a powerful new tool for bringing it under control."

The Institut National de Recherche Biomedicale, the DRC's national public health and biomedical research institute, leads the vaccines trial with the University of Antwerp, in collaboration with WHO, Epicentre, Medecins Sans Frontieres and the Africa Centres for Disease Control and Prevention, among others. Development of the candidates is supported by the Coalition for Epidemic Preparedness Innovations.

Tumaini is built to test multiple vaccine candidates within a single trial using a ring-vaccination approach that enrolls contacts of people with confirmed Bundibugyo virus disease. It builds on the design pioneered during the West Africa Ebola outbreak a decade ago, when a trial in Guinea established the efficacy of Ervebo against Zaire ebolavirus. Ervebo is the first vaccine being evaluated in a Tumaini trial against Bundibugyo virus, and four vaccination rings are already in place.

Treatment research is advancing in parallel. The WHO-sponsored PARTNERS trial is evaluating whether the monoclonal antibody MBP134, the antiviral remdesivir, or a combination of both can improve survival in confirmed Bundibugyo virus disease. Maftivimab will soon be added as a potential treatment, and a post-exposure prophylaxis study with obeldevisir is under way. Treatment findings are expected in the coming months, with vaccine results expected in early 2027.

For suppliers serving outbreak response, the announcement signals where near-term demand concentrates: diagnostics and sample transport for ring vaccination and case confirmation, cold-chain capacity at peripheral health facilities, and consumables for monoclonal antibody and antiviral administration. It also shows how regulatory pathways compress during emergencies, with candidates moving through national approvals alongside trial protocols. Suppliers with documented quality systems, WHO prequalification or a credible route to it, and the ability to ship into Central African logistics hubs at short notice remain the practical bottleneck in response timelines.

WHO is supporting the research through its R&D Blueprint and Health Emergencies Programme, providing protocols, technical advice, partner coordination and operational support.

Source: WHO, Two new candidate vaccines to join Ebola trial as treatment research advances, https://www.who.int/news/item/04-11-2026-two-new-candidate-vaccines-to-join-ebola-trial-as-treatment-research-advances