The World Health Organization has recommended two experimental vaccines for inclusion in a clinical trial in the Democratic Republic of the Congo, in a new attempt to develop protection against the strain of Ebola driving the country’s deadliest outbreak on record.
The two candidates — ChAdOx1 BDBV, developed by the University of Oxford with the Serum Institute of India, and mRNA-1469, developed by the American biotechnology company Moderna — were designed specifically for the Bundibugyo virus, the species behind the current outbreak. No licensed vaccine or specific treatment exists for Bundibugyo disease.
The recommendation came from the WHO’s independent Technical Advisory Group on Candidate Vaccines Prioritization, which reviewed the available evidence this week. It marks the first time vaccines made specifically for the Bundibugyo virus will be evaluated during an outbreak of the disease.
The candidates will join the Tumaini trial — named after the Swahili word for “hope” — which began on 23 October in Bunia, the capital of Ituri province and the epicentre of the outbreak. The trial is led by the DRC’s National Institute for Biomedical Research, with support from the WHO and international partners, and uses ring vaccination, enrolling the contacts of confirmed patients.
So far the trial has been testing Ervebo, a vaccine licensed for Ebola disease caused by the Zaire species, which is not designed for Bundibugyo. The two new candidates will enter the trial once national regulatory approvals are in place.
The scale of the outbreak underlines the urgency. As of 1 November, the DRC had recorded more than 10,500 confirmed cases and 5,126 deaths, according to the WHO, making it the largest Ebola outbreak in the country’s history. The Africa Centres for Disease Control and Prevention has put the death toll above 5,300, with a case fatality rate of more than 50 per cent. The outbreak was declared in May and has now run for nearly six months.
The WHO said initial results from the vaccine trial are expected in early 2027. A separate study, the PARTNERS trial, is testing whether the monoclonal antibody MBP134, the antiviral remdesivir, or a combination of the two can improve survival among confirmed patients, with early findings expected in the coming months.
WHO Director-General Tedros Adhanom Ghebreyesus cautioned that vaccination alone would not be enough to end the outbreak, describing the vaccines as a potential additional tool alongside case finding, contact tracing and safe care.
Sources: UN News — “Two new Ebola vaccines to join DR Congo clinical trial” (https://news.un.org/en/story/2026/11/1168742); World Health Organization; Medical Xpress — “WHO approves clinical trials on two new Ebola vaccines” (https://medicalxpress.com/news/2026-11-clinical-trials-ebola-vaccines.html).
