Congo Ebola hits 10,060 cases with no Bundibugyo vaccine

Key takeaways

• Congo's health ministry counted 10,060 confirmed Ebola cases on 27 October 2026, the Associated Press reported, and nearly half of those patients have died.
• The outbreak is caused by Bundibugyo virus, a different species from the Zaire ebolavirus that the licensed Ervebo vaccine was built against. WHO says no approved vaccine or specific treatment exists for it.
• Case growth has slowed from roughly 80 a day in August and September to about 50 a day in the past week, but about 80% of recent cases were not among monitored contacts, according to AP.
• A Phase 2/3 vaccine trial called TUMAINI started in Bunia on 23 October. It is testing Ervebo for cross-protection. An Oxford-designed Bundibugyo vaccine, ChAdOx1 BDBV, has been in a Phase 1 safety trial since July.
• The virus has now been recorded in five countries: Congo, Uganda, France, Kenya and Nigeria. Only Congo, Kenya and Nigeria have active cases.

Congo's Bundibugyo Ebola outbreak reached 10,060 laboratory-confirmed cases on Tuesday, 27 October, five months after it was declared, and there is still no licensed Ebola Bundibugyo vaccine. A trial is now testing Ervebo for cross-protection.

The ministry's count stood at 10,060, according to the Associated Press. That makes this the largest Ebola outbreak in Congo's history and the fastest-growing on record. The milestone matters for science as well as for public health. This is the first time Bundibugyo virus has spread at this scale, so doctors are fighting it with tools designed for a different virus.

Ebola Bundibugyo vaccine: why Ervebo is not enough

"Ebola" is not one virus. The genus Orthoebolavirus includes several species. Zaire ebolavirus caused the 2014–2016 West Africa epidemic and most of Congo's earlier outbreaks. Bundibugyo virus is a separate species, named after Bundibugyo district in western Uganda, the site of its first recorded outbreak.

The difference matters for countermeasures. Ervebo is the only licensed Ebola vaccine, and it was developed against the Zaire species, not Bundibugyo. In its 23 October Disease Outbreak News, the World Health Organization repeats that "no approved vaccines or specific treatments currently exist" for Bundibugyo virus disease. Patients therefore depend on supportive care: fluids, electrolytes and treatment of complications. Outbreak control relies on finding cases early, tracing contacts, protecting health workers and holding safe burials.

Before 2026, Bundibugyo virus was known from only two outbreaks. WHO's May 2026 outbreak notice describes them: Uganda in 2007, and Congo in 2012, which had 59 cases and 34 deaths. Case fatality in those outbreaks ranged from about 30% to 50%. The current outbreak's crude fatality rate was 48.3% as of 20 October, WHO said. In North Kivu it was 55.9%.

From 85 cases to more than 10,000

Congo and Uganda declared the outbreak on 15 May 2026, and WHO declared it a public health emergency of international concern two days later. The official counts below show how quickly it grew. They come from different agencies and reporting dates, so small differences reflect reporting lags rather than corrections.

Simple arithmetic on these figures shows a slowdown. About 3,800 cases were added between early August and 23 September, roughly 80 a day. Between 23 September and 20 October the pace was about 67 a day. Between 20 and 27 October it fell to about 50 a day. The slowdown is real but fragile. AP reported that about 80% of recent cases did not come from people already being followed as contacts, which suggests that chains of transmission are going undetected. Africa CDC's benchmark for an outbreak that is largely under control is at least 95% of cases coming from known contacts, AP said.

The spread inside Congo is also wider. At the start, the outbreak was in three health zones. It now covers 66 health zones in eight provinces, according to WHO and AP. Ituri is the epicentre, with 7,040 cases and 3,271 deaths as of 20 October, according to WHO, followed by North Kivu with 2,146 cases.

The vaccine trials: Ervebo, TUMAINI and ChAdOx1 BDBV

Testing whether Ervebo cross-protects

Because Ervebo is already licensed and stockpiled, scientists want to know whether it gives any protection against Bundibugyo. In August, WHO experts recommended prioritising it for a randomised trial. Al Jazeera reported on the animal evidence behind that advice: in a study in non-human primates, three of four vaccinated animals survived Bundibugyo infection, compared with one of four unvaccinated controls. Gavi holds a stockpile of 500,000 Ervebo doses, Al Jazeera added.

The evidence has limits. WHO's vaccine advisory group, TAG-CVP, warned that protection against illness and transmission may be limited, even if some protection against death is possible. "Expectations need to be managed about its likely protective effect," the group said, according to Al Jazeera.

TUMAINI: the pivotal trial in Bunia

The TUMAINI trial, whose name means "hope" in Swahili, enrolled its first participants in Bunia, Ituri province, on 23 October, WHO said. WHO describes it as a pivotal Phase 2/3 trial of candidate Bundibugyo vaccines. Africanews reported that Congo's National Institute for Biomedical Research (INRB) leads it, with technical and logistical support from WHO, and that it vaccinates contacts of confirmed cases. Kenya's Standard newspaper reported that Ervebo will be tested as part of the effort, and that Kenya has asked Africa CDC and WHO for 10,000 vaccine doses for frontline health workers.

Oxford's Bundibugyo-specific candidate

The most advanced vaccine designed specifically for Bundibugyo is ChAdOx1 BDBV from the University of Oxford, with the Serum Institute of India as manufacturer. A first volunteer was vaccinated in Oxford in July, Africanews reported, citing AFP. The Phase 1 trial plans to enrol 50 healthy adults, and the Serum Institute of India has already manufactured 620,000 doses. "We've taken this vaccine candidate from concept to clinic in just eight weeks," Oxford researcher David Pulido-Gomez said. A Phase 1 trial tests safety and immune response. It cannot show whether the vaccine prevents infection, so efficacy data must come from field trials such as TUMAINI.

On treatment, WHO said in July that patient enrolment had begun in a clinical trial to identify effective therapies. No product has yet been approved for Bundibugyo.

Spread beyond Congo: Kenya, Nigeria and Europe

The outbreak has spread farther across Africa than any previous Ebola outbreak, AP said. The European Centre for Disease Prevention and Control counted nine confirmed cases in Kenya as of 25 October, including two deaths, all linked to the first imported case. Nigeria confirmed one imported case in Abuja on 20 October. The patient had travelled to Uganda, WHO's Africa office said, and ECDC put the number of identified contacts at 53. Bullquill covered the first cases in our report on Ebola reaching Kenya and Nigeria.

Uganda recorded 20 confirmed cases and has no active cases, according to the US CDC; ECDC says its outbreak has ended. Uganda is now requiring a 21-day quarantine for citizens returning from Congo. France recorded one case, who has recovered. ECDC rates the risk for people living in the EU/EEA as very low. WHO advises against travel or trade restrictions on affected countries.

What it means

Scientifically, the 10,000-case mark makes this the largest dataset on Bundibugyo virus ever collected. That should sharpen estimates of its fatality rate, incubation and transmission. It also exposes a gap in preparedness: the world stockpiled a vaccine for one Ebola species, and the outbreak came from another. If TUMAINI shows that Ervebo gives partial protection, existing stockpiles could be used quickly. If it does not, the response will depend on Bundibugyo-specific candidates such as ChAdOx1 BDBV, which are months behind.

Operationally, the slowing case curve is fragile. "Ebola is crossing borders. Our response must move faster, with stronger coordination," Africa CDC head Jean Kaseya said, according to AP. Responders face armed conflict, unpaid wages and attacks: a nurse was killed on Saturday while responding to an alert in Bafwasende, Tshopo province, AP reported. African health ministers are due to hold a virtual summit on Wednesday, 28 October. For more updates, follow Bullquill's Ebola coverage.