Congo’s Ebola outbreak has killed nearly half of everyone it infected

As of August 21, 2026, the Democratic Republic of the Congo had confirmed 5,458 cases of Ebola disease and 2,606 deaths in the outbreak caused by Bundibugyo virus — a case fatality rate of 48 percent, meaning the disease has killed just under half of everyone it has infected. Case investigators with the CDC 2026 Ebola Response International Epidemiology and Laboratory Task Force, led by Dumazedier Kabasele, describe it as the second-largest Ebola outbreak ever recorded.

The pace has been as striking as the toll. Roughly 5,000 cases accumulated in about 100 days, spreading to six of the country’s 26 provinces and 57 of the 151 health zones inside them. Ituri province, where the outbreak began, remains the epicenter, accounting for the large majority of reported infections.

Why containment measures are falling behind the outbreak’s pace

The investigators’ own operational indicators, published in the CDC’s Morbidity and Mortality Weekly Report, show nearly every response target missed during the three-week period ending August 21. Alerts were investigated within 24 hours 83 percent of the time, short of a 90 percent goal; contact tracers identified an average of just 10.6 contacts per confirmed case against a target of at least 20; and only 82 percent of daily contact tracing was completed, versus a 95 percent target. The report concludes that these gaps, “together with continued geographic expansion of the outbreak,” point to uncontrolled spread rather than a response gaining ground.

Perhaps the most telling figure is this: only 15 to 20 percent of new cases as of mid-July were traced back to people already identified as contacts of a known patient, far below the 90 percent target investigators consider necessary to interrupt transmission. That means the large majority of new infections are occurring through chains of transmission nobody has mapped yet. Laboratory testing was completed for 72 percent of validated alerts, also below a 90 percent target, and of those tests that were run, 24 percent came back positive — a positivity rate the report’s target sets at zero.

More than half of confirmed deaths are happening outside treatment

Fifty-nine percent of confirmed Bundibugyo virus deaths occurred outside an Ebola treatment unit, against a target of zero, which the CDC task force says points to insufficient treatment capacity, fear of the units themselves, and continued spread through transmission chains investigators have not identified. National bed occupancy across treatment units averaged 64 percent, technically under the 80 percent ceiling investigators use as a warning line, but some individual health zones reported occupancy as high as 140 percent, meaning patients were being turned away or treated without adequate isolation. Fewer than half of the affected health zones — 49 percent — had even one team trained to carry out safe and dignified burials, the practice credited with cutting funeral-associated transmission in past outbreaks.

The World Health Organization’s own count, updated five days after the CDC’s snapshot, shows the scale continuing to grow: as of August 26, 2026, the World Health Organization reported 5,794 confirmed cases and 2,786 deaths, a case fatality ratio of 48.1 percent, spread across 60 health zones rather than the CDC’s 57. The two counts differ slightly because they were taken days apart during a fast-moving outbreak, but they tell the same story: a death rate holding steady near half of all confirmed infections even as the total keeps climbing.

A complex humanitarian emergency shapes the response

The outbreak is unfolding inside one of the world’s more difficult humanitarian settings. The WHO update describes more than 26 million people in the Democratic Republic of the Congo facing acute food insecurity, with an estimated one million people internally displaced in Ituri province alone. Armed conflict and population displacement restrict where response teams can safely operate, disrupt contact tracing, and push overcrowded, under-served communities toward exactly the conditions that let a hemorrhagic fever spread undetected.

Even against that backdrop, countermeasures have started moving. Vaccination of health care workers using the Ervebo vaccine — licensed against the related Zaire strain of Ebola virus, though not proven effective against Bundibugyo virus specifically — began on August 27 in parts of Kisangani, and the World Health Organization is sponsoring a treatment trial, known as PARTNERS, that had enrolled more than 250 confirmed patients across three clinical sites in Ituri as of late August. The World Health Organization first classified the outbreak as a public health emergency of international concern on May 17, 2026, two days after the Congolese and Ugandan health ministries jointly declared outbreaks in their respective countries.

What the case investigators say still needs to happen

Kabasele and the task force’s co-authors lay out five areas where the response has to improve simultaneously to bend the outbreak’s trajectory: expanding community-based surveillance so alerts reach investigators faster, improving the completeness and speed of contact tracing, adding treatment and isolation capacity in the hardest-hit health zones, increasing laboratory testing capacity so cases are confirmed faster, and ensuring every affected health zone has a functioning safe-burial team. Those five domains were calibrated against the DRC’s own 2018 Ebola outbreak, the country’s last major epidemic, which the current outbreak has already dwarfed in scale by the task force’s own comparison.

The contrast with where this outbreak started is stark. A separate CDC report on the same outbreak had counted just 378 confirmed cases and 63 deaths as of June 2, 2026, roughly two and a half weeks after the Democratic Republic of the Congo and Uganda first declared their outbreaks on May 15. Corresponding author Sascha Ellington and colleagues wrote in the August report that the missing data and operational shortfalls documented since then, “together with continued geographic expansion of the outbreak, indicate uncontrolled expansion” — a conclusion drawn not from projection, but from the response’s own measured distance behind the disease it is trying to stop.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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