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Congo's Ebola outbreak tops 10,000 cases as vaccine trial begins

Congo's Ebola outbreak has passed 10,000 confirmed cases, with 4,887 deaths as of Oct. 25, according to the country's health authorities. It is caused by the Bundibugyo strain, which has no approved vaccine or treatment, and a trial of vaccine candidates began Oct. 23. Deaths passed 5,000 by Oct. 31, AP reported.

By US Brief desk · Updated 2026-11-01T10:15:00-08:00

AI-assisted · US Brief desk · Sources listed below

What happened

Congo has recorded 10,060 confirmed Ebola cases and 4,887 deaths as of Oct. 25, a fatality rate of about 48.6%, according to the country's health authorities as reported by Xinhua. AP reported that the outbreak has topped 10,000 cases as officials race to slow its spread to other African countries.

Why it matters

It is the largest Bundibugyo outbreak on record and the second-largest Ebola outbreak of any kind, after the 2014–16 West Africa epidemic, the Institute of Tropical Medicine says. It's caused by Bundibugyo virus, a strain with no approved vaccine or treatment, so the tools that helped stop recent Congo outbreaks don't directly apply.

More context

Update, Nov. 1: Deaths have passed 5,000. Congo had recorded 10,351 confirmed cases and 5,026 deaths, AP reported Oct. 31, citing health ministry data, with cases in 67 of the country's 178 health zones. Congo's health ministry has since published a higher death toll, 5,340 as of Oct. 29, after Ituri province revised its data, so counts differ by source. Kenya has reported nine cases and two deaths, according to the European Centre for Disease Prevention and Control (ECDC).

Where it is: Cases are spread across 67 health zones (as of Oct. 31, AP) in eight of Congo's 26 provinces. Ituri province in the northeast is the epicenter, with about 71.7% of cases. The outbreak has also reached Uganda, Kenya and Nigeria, and France has reported one imported case.

The vaccine trial: On Oct. 23, the first participant was vaccinated in Bunia in Tumaini, a Phase 2/3 trial co-led by Congo's national biomedical research institute (INRB) and the University of Antwerp. It uses ring vaccination of high-risk contacts. The first candidate is Ervebo, licensed against a different Ebola strain; two Bundibugyo-specific candidates from Moderna and from Oxford with the Serum Institute of India are being prepared. Gavi has committed up to $40 million for manufacturing readiness.

Timeline: May 15, outbreak declared; WHO and Africa CDC declare emergencies in the following days. Oct. 21, 9,552 confirmed cases and 4,602 deaths, per ITM. Oct. 23, vaccine trial begins. Oct. 25, 10,060 cases and 4,887 deaths, per Congo's health authorities. Comparing those two counts, that's roughly 500 new confirmed cases in four days.

What's still unknown: Whether any candidate vaccine works against Bundibugyo, how quickly trial results could come, and how many cases go unreported in conflict-affected parts of Ituri. U.S. travel guidance is on the CDC's situation page.

10 listed sources

References listed by US Brief; a source count is not a verification score.

Editorial sourcing notes

Sourcing: AP; Congo health-ministry figures as reported by China's state-run Xinhua news agency; the Institute of Tropical Medicine's Oct. 23 trial announcement; WHO, ECDC and CDC outbreak pages. Case counts differ slightly by source and reporting date. Images are file images of Ebola virus, not the Bundibugyo strain specifically. Updated Nov. 1 with AP's Oct. 31 figures and the health ministry's revised death toll; the Oct. 25 figures below are kept as reported at the time.

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