The World Health Organization has recommended two new Ebola vaccines for clinical trials in the Democratic Republic of the Congo, where a deadly outbreak has killed more than 5,100 people and infected more than 10,600 since May.
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 — are the first vaccines designed specifically for the Bundibugyo species of the Ebola virus. They will join the ongoing Tumaini trial in eastern DRC once the country's authorities grant national approval, the WHO announced on 5 November.
The outbreak, caused by the rare Bundibugyo virus, is the largest in the DRC's history and, by case numbers, the second-largest Ebola outbreak ever recorded, after the 2014–2016 epidemic in West Africa that killed more than 11,000 people.
What the WHO announced
The WHO's independent Technical Advisory Group on Candidate Vaccines Prioritization recommended both candidates for further clinical evaluation after reviewing the available preclinical and early clinical evidence. The recommendation followed a review of the scientific evidence by expert groups, WHO Director-General Tedros Adhanom Ghebreyesus said.
“The fact that these vaccines are ready to enter clinical trials is a testament to the power of science and partnership,” Tedros said. He stressed that while vaccines alone will not end the outbreak, “they could become a powerful new tool for bringing it under control”.
The two new candidates will be added to the Tumaini trial — named after the Swahili word for “hope” — which began enrolling participants 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 research partners.
The outbreak so far
The DRC's health ministry declared the outbreak in Ituri province on 15 May 2026. Two days later, the WHO declared it a public-health emergency of international concern. Nearly six months on, the virus has spread to eight provinces in eastern and north-eastern DRC, and infections have also been recorded in other African countries, according to the Africa Centres for Disease Control and Prevention.
The latest figures show the scale of the crisis:
| Measure | Figure | Source and date |
|---|---|---|
| Confirmed cases | 10,603 | DRC Ministry of Health, 2 November |
| Deaths | 5,163 | DRC Ministry of Health, 2 November |
| Case fatality rate | 48.7% | DRC Ministry of Health, 2 November |
| Cases in Ituri province | 7,431 (3,492 deaths) | European Centre for Disease Prevention and Control, 1 November |
| Cases in Nord-Kivu province | 2,518 (1,395 deaths) | European Centre for Disease Prevention and Control, 1 November |
The European Centre for Disease Prevention and Control, which tracks the outbreak independently, recorded 10,532 confirmed cases and 5,126 deaths as of 1 November, and cautioned that the figures remain subject to review and that the outbreak could be larger than detected. Ituri remains the worst affected province, followed by Nord-Kivu.
Why this strain is different. Ebola disease is caused by several species of ebolavirus. The Bundibugyo species is comparatively rare, and there is currently no licensed vaccine or approved antiviral treatment designed specifically for it. The vaccine already in use against Ebola, Ervebo, was developed for the Zaire species — the strain behind the West Africa epidemic — and is now being tested in the Tumaini trial to see whether it also protects against Bundibugyo.
How the Tumaini trial works
Tumaini is designed to test several vaccine candidates inside a single trial, using a ring-vaccination approach: the contacts of people with confirmed Ebola Bundibugyo, and the contacts of those contacts, are vaccinated to form a protective ring around each case. The WHO and its partners pioneered the strategy during the West Africa outbreak a decade ago, when a trial in Guinea established the efficacy of the Ervebo vaccine.
Four vaccination rings have been set up so far, and several more are being prepared, according to the WHO. The two new candidates will enter the trial following national approvals by the DRC authorities.
Research into treatments is moving forward in parallel. A separate WHO-supported trial, known as PARTNERS, is investigating whether the monoclonal antibody MBP134, the antiviral remdesivir, or a combination of the two can improve survival in people already infected, according to the medical publication EMJ. Initial findings from the treatment trial are expected in the coming months, with preliminary vaccine-trial results anticipated in early 2027.
A British health worker among the cases
The outbreak's reach beyond the DRC was underlined on 4 November, when the UK government confirmed that a British healthcare worker sent to help fight the outbreak had tested positive for the virus and been airlifted back to the United Kingdom for specialist treatment. It is the first British national known to have caught the disease during the current outbreak. Ghana's health ministry said it had not recorded any Ebola case and was keeping watch for travellers.
What is not yet known. The two new vaccines have been recommended for trial — they have not been approved for general use, and there is no evidence yet that they protect against Bundibugyo disease in people. The trial results, expected in early 2027, will be the first real test. The WHO has also been clear that vaccines alone will not end this outbreak: case finding, contact tracing, safe burials and community trust remain the core of the response.
Frequently asked questions
What is the Bundibugyo virus?
Bundibugyo is one of the species of ebolavirus that cause Ebola disease. It was first identified in Uganda in 2007. Like other Ebola viruses it spreads through direct contact with the blood or body fluids of a sick person, and it causes fever, severe weakness, vomiting, diarrhoea and, in many cases, bleeding. The current DRC outbreak is caused by this species.
Why has it taken so long to get a vaccine for this strain?
Bundibugyo outbreaks have been rare and comparatively small, so vaccine development for this strain lagged behind the Zaire species, which caused the large West Africa epidemic. The current outbreak — the largest Bundibugyo outbreak on record — is the first time vaccines designed specifically for this strain are being tested during an active outbreak.
How does ring vaccination work?
When a case is confirmed, health workers identify the patient's contacts, and the contacts of those contacts, and offer them vaccination. The aim is to build immunity in the ring of people most likely to be exposed next, cutting off chains of transmission. The approach was first used successfully against smallpox and later proved the Ervebo vaccine in Guinea in 2015.
Is there a treatment for Ebola?
There is no approved treatment specifically for Bundibugyo disease. Care focuses on rehydration, managing symptoms and treating other infections, which improves survival. The PARTNERS trial is testing whether the antibody MBP134 and the antiviral remdesivir can improve outcomes for people already infected.
How dangerous is the outbreak for people outside the DRC?
Ebola spreads through close contact with a sick person's body fluids, not through the air, so the risk to the general public outside the affected region remains low. Health authorities in neighbouring countries and further afield are screening travellers and preparing isolation facilities, as Ghana and the UK have done this week. The WHO has not recommended travel or trade restrictions.
Key takeaways
- The WHO has recommended two new vaccines — Oxford/Serum Institute's ChAdOx1 BDBV and Moderna's mRNA-1469 — for trials in the DRC. They are the first designed specifically for the Bundibugyo Ebola virus.
- The outbreak has killed 5,163 people and infected 10,603, according to the DRC health ministry — the largest Ebola outbreak in the country's history.
- The vaccines will join the Tumaini ring-vaccination trial in Bunia, Ituri province, once DRC authorities approve them. Preliminary results are expected in early 2027.
- There is still no licensed vaccine or approved treatment for Bundibugyo disease, and the WHO says vaccines alone will not end the outbreak.
What to watch next
The immediate question is how quickly the DRC authorities approve the two candidates for the Tumaini trial, and how fast new vaccination rings can be set up around fresh cases in Ituri and Nord-Kivu. The next ECDC and DRC health ministry updates will show whether the outbreak is still expanding into new provinces or stabilising. And the PARTNERS treatment trial, with initial findings due in the coming months, could give doctors their first proven therapy for Bundibugyo disease — a result that would matter well beyond this outbreak.
