Oxford and Moderna Ebola Vaccines Set for First Trial Against Bundibugyo Outbreak

The two vaccine candidates are ChAdOx1, developed by the University of Oxford in partnership with the Serum Institute of India, and Moderna's mRNA-1469, which uses messenger RNA technology.

Two experimental Ebola vaccines designed to protect against Bundibugyo virus could soon be tested during an active outbreak in the Democratic Republic of the Congo (DRC), following recommendations from expert groups convened by the World Health Organization (WHO). The vaccines are expected to join the ongoing Tumaini clinical trial once national authorities approve their inclusion, creating the first opportunity to evaluate vaccines specifically developed for Bundibugyo virus during an outbreak. Researchers hope the findings will help identify new ways to protect communities exposed to the virus and strengthen future responses to similar health emergencies.

The two vaccine candidates are ChAdOx1, developed by the University of Oxford in partnership with the Serum Institute of India, and Moderna's mRNA-1469, which uses messenger RNA technology. WHO's independent Technical Advisory Group on Candidate Vaccines Prioritization recommended both vaccines for further clinical evaluation after reviewing available laboratory research and early clinical evidence. Their inclusion in the trial represents an important development in efforts to understand whether these vaccines can provide effective protection against Bundibugyo virus disease.

WHO Director-General Dr Tedros Adhanom Ghebreyesus described the progress as an example of what scientific cooperation can achieve, recognising the contributions of researchers, healthcare workers, international partners and people participating in the trial. He emphasised that vaccines alone cannot end the outbreak, but successful candidates could provide health authorities with another valuable tool to reduce infections and protect vulnerable communities. The participation of people exposed to the virus will help researchers gather evidence needed to understand vaccine effectiveness and guide future public health decisions.

New Vaccines Bring Hope for Stronger Ebola Protection

The Tumaini vaccine trial is being led by the DRC's Institut National de Recherche Biomédicale (INRB), working closely with Belgium's University of Antwerp and several international health organisations. Partners include WHO, Epicentre, Médecins Sans Frontières, the Institute of Tropical Medicine in Antwerp, Africa Centres for Disease Control and Prevention, the DRC Ministry of Health and the country's Institut National de Santé Publique. Investments from the Coalition for Epidemic Preparedness Innovations (CEPI) have supported the rapid development of vaccine candidates, helping researchers prepare potential protective tools for outbreaks involving different Ebola viruses.

The trial allows researchers to evaluate multiple vaccine candidates within a single research programme, making it possible to gather evidence about different approaches to preventing Bundibugyo virus disease. Oxford's ChAdOx1 and Moderna's mRNA-1469 will enter the programme only after the necessary national approvals have been granted, and the required clinical arrangements are completed. Studying these vaccines during an outbreak could provide valuable information about their performance in real-world conditions, including whether they can reduce the risk of illness among people exposed to infected individuals.

How Ring Vaccination Could Help Control the Outbreak

The Tumaini trial follows a ring-vaccination approach, which involves identifying people who have been in contact with someone diagnosed with Bundibugyo virus disease and enrolling eligible contacts in the research. Four vaccination rings have been established, with additional groups being prepared to include contacts of people who became ill or died from Ebola. This approach allows researchers to study vaccine effectiveness among people with known exposure risks and could provide useful evidence for improving outbreak responses.

The strategy draws on experience from the Ebola outbreak in West Africa about a decade ago, when WHO and its partners conducted a major vaccine trial in Guinea. That research demonstrated the effectiveness of Ervebo against Ebola virus, commonly known as Zaire ebolavirus, and helped establish ring vaccination as an important research approach during outbreaks. Ervebo is the first vaccine being evaluated in the current Tumaini trial to determine whether it offers protection against Bundibugyo virus, with the two newly recommended candidates expected to expand the research once approved.

New Treatment Research Could Improve Patient Survival

Scientists are investigating possible treatments for people who have contracted Bundibugyo virus disease through the WHO-sponsored PARTNERS clinical trial, launched in July 2026. The research is examining whether the monoclonal antibody MBP134, the antiviral medicine remdesivir or a combination of both can improve survival among patients with confirmed infections. Another treatment called maftivimab is expected to enter the trial, and a separate study is evaluating obeldevisir as a possible preventive medicine after exposure to the virus.

WHO is supporting these studies through its Research and Development Blueprint and Health Emergencies Programme, helping researchers develop protocols, coordinate partnerships and conduct scientifically rigorous and ethical research during the outbreak. Initial findings from the treatment trials are expected in the coming months, with results from the Tumaini vaccine trial anticipated in early 2027. The research could improve understanding of how Bundibugyo virus disease can be prevented and treated, giving health authorities stronger scientific evidence to protect communities and reduce deaths during future outbreaks.

10 Tags: World Health Organization, Ebola Vaccine, Bundibugyo Virus, Democratic Republic of the Congo, Tumaini Clinical Trial, Oxford University, Moderna, Ring Vaccination, Ebola Treatment Research, Global Health Security