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). The recommendation marks the first time vaccines specifically designed to protect against Bundibugyo virus, the virus responsible for the current outbreak, will be evaluated during an outbreak of the disease.
The two vaccine 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 Vaccine Prioritization recommended both for further clinical evaluation this week, based on available preclinical and early clinical evidence. The companies were informed on Monday. The vaccine 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. “I thank the scientists, health workers and partners in the DRC and around the world who have brought us to this point, and especially the people taking part in the trial. Their participation will generate vital evidence that could help save lives. 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 Biomédicale, the DRC's national public health and biomedical research institute is leading the vaccines trial, with support from the University of Antwerp, Belgium, WHO, Epicentre, Médecins Sans Frontières, the Institute of Tropical Medicine of Antwerp, and the Africa Centres for Disease Control and Prevention. The rapid development of candidate vaccines is made possible by investments by the Coalition for Epidemic Preparedness Innovations.
Tumaini is designed 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 an approach pioneered by WHO and partners during the West Africa Ebola outbreak a decade ago, when a landmark trial in Guinea established the efficacy of Ervebo against Ebola virus, also known as Zaire ebolavirus. Ervebo is the first vaccine being evaluated in a Tumaini trial to now assess efficacy against Bundibugyo virus.
Four vaccination rings are already in place, with several more being prepared. The rings include contacts of people who became ill or died from Ebola.
Research into potential treatments is also advancing. The WHO-sponsored PARTNERS trial, launched in July, is evaluating whether the monoclonal antibody MBP134, the antiviral remdesivir, or a combination of both can improve survival among patients with confirmed Bundibugyo virus disease. In addition, maftivimab will soon be added to the trial to assess its use as a potential treatment. A complementary post-exposure prophylaxis study with obeldevisir is underway.
WHO is supporting research during the Bundibugyo virus disease outbreak through its R&D Blueprint and Health Emergencies Programme, including developing research protocols, providing strategic and technical advice, coordinating among partners, and providing operational support to embed rigorous and ethical studies within the response.
Initial findings from the treatment trials are expected in the coming months, with results from the vaccine trial expected in early 2027.
About WHO
Dedicated to the well-being of all people and guided by science, WHO leads and champions global efforts to give everyone, everywhere, an equal chance at a safe and healthy life. We are the United Nations’ agency for health that connects nations, partners and people in more than 150 locations – leading the world’s response to health emergencies, preventing disease, addressing the root causes of health issues and expanding access to medicines and health care. Our mission is to support all countries to promote, provide and protect health. “Together for health. Stand with science”, the theme of World Health Day 2026, marks a year-long campaign to highlight science as the foundation for protecting health and well-being worldwide.