WHO Adds the First Bundibugyo-Specific Ebola Vaccines to a Congo Trial as Cases Pass 10,600

Two vaccines built specifically against Bundibugyo virus, the Ebola species driving the outbreak in the Democratic Republic of the Congo, are set to enter a clinical trial there for the first time. Expert groups convened by the World Health Organization recommended adding the candidates to the ongoing Tumaini trial, WHO said on Nov. 4, 2026, as confirmed cases climbed past 10,600. The Bundibugyo Ebola vaccine trial will start testing the two shots only after Congolese national approvals.

The 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 based on preclinical and early clinical evidence, and the developers were told on Monday, Nov. 2, according to the WHO release. Neither is an approved vaccine.

“Vaccines alone will not end this outbreak, but they could become a powerful new tool for bringing it under control,” WHO Director-General Tedros Adhanom Ghebreyesus said.

How the Tumaini trial works

Tumaini is designed to test several vaccine candidates inside one study using ring vaccination, which enrolls the contacts of people with confirmed Bundibugyo virus disease. The approach copies the method WHO and partners used in Guinea during the West Africa epidemic a decade ago, when a trial showed that Ervebo protected against the Zaire species of Ebola. Ervebo is already being evaluated in Tumaini to see whether it also protects against Bundibugyo, and WHO said four vaccination rings are in place with several more being prepared.

Congo’s Institut National de Recherche Biomédicale leads the trial with the University of Antwerp, working with WHO, Epicentre, Médecins Sans Frontières, the Institute of Tropical Medicine of Antwerp, the Africa Centres for Disease Control and Prevention and Congo’s health ministry. The Coalition for Epidemic Preparedness Innovations funded the rapid development of the candidates, WHO said.

Treatment research is moving in parallel. The WHO-sponsored PARTNERS trial, launched in July, is testing the monoclonal antibody MBP134, the antiviral remdesivir, or both together in patients with confirmed infection, and maftivimab will soon be added. A separate post-exposure prevention study of obeldevisir is under way. In a UN News interview released Nov. 6, Meg Doherty, who heads WHO’s Science for Health Department, discussed what the trial could mean for bringing the outbreak under control.

What the data shows

WHO’s latest Disease Outbreak News, published Nov. 6, counted 10,668 confirmed cases and 5,198 deaths as of Nov. 3 across 67 health zones in eight provinces. That is 964 more cases and 511 more deaths than in the previous update on Oct. 23. Active transmission continues in 51 of the 67 affected zones.

Ituri accounts for 7,485 of the cases, about 70% of the total by The Boston Report’s calculation from WHO figures, with 3,532 deaths. Nord Kivu follows with 2,593 cases and the highest provincial fatality ratio, 54.8%. Momentum has shifted, though: in the seven days to Nov. 3, Nord Kivu reported the most new cases, 232, and in the 21 days to Nov. 3 it logged 640 new cases against Ituri’s 710.

Two numbers show why the trial matters. First, of the 512 deaths reported since Oct. 21, 335 occurred in communities rather than treatment centers, which WHO said shows trouble with early detection and access to care, especially for young children. Second, contact tracing is short of target: the share of contacts seen daily over 14 days averaged 86%, against the 95% threshold. Tshopo was lowest at 71% and Nord Kivu at 82%. Ring vaccination depends on finding contacts quickly, so those gaps limit how fast any vaccine can be deployed.

Beyond Congo

Cases have been reported in five countries since the outbreak was declared on May 15, 2026: Congo, France, Kenya, Nigeria and Uganda. WHO said the outbreaks in France and Uganda have been controlled since August. Kenya’s total stands at nine confirmed cases and two deaths, with no new cases since Oct. 19 and contact follow-up due to end Nov. 11. Nigeria reported one imported case in Abuja on Oct. 20; the patient was medically evacuated to Geneva. The United Kingdom reported on Nov. 5 that a confirmed health worker case had been evacuated to London. WHO continues to advise against travel or trade restrictions.

For the full timeline, case counts and earlier reporting, see our Ebola outbreak tracker. We reported when the outbreak passed 10,000 cases in late October and when the death toll and fatality rate were updated earlier this month.

What comes next

The two new candidates still need national regulatory approval before anyone receives them in Tumaini, and WHO has not given a start date. Results on whether ChAdOx1, mRNA-1469 or Ervebo actually protect against Bundibugyo will depend on how many rings are vaccinated and how quickly. Until then, WHO’s own figures point to contact tracing and earlier care as the immediate levers on an outbreak now nearly six months old.

Sources

• WHO: Two new candidate vaccines to join Ebola trial as treatment research advances (Nov. 4, 2026)
• WHO Disease Outbreak News: Ebola disease caused by Bundibugyo virus, DRC, Kenya and Nigeria (Nov. 6, 2026)
• UN News: DR Congo Ebola outbreak: Vaccine trial brings new hope (Nov. 6, 2026)