DR Congo's Ebola outbreak passes 9,000 cases, becomes deadliest in country's history

The Democratic Republic of Congo's Ebola outbreak has passed 9,000 confirmed cases, the country's health ministry said on Tuesday, making the five-month-old epidemic the deadliest Ebola outbreak ever recorded in the country and the second-largest in history, behind only the 2014-2016 West African epidemic that killed more than 11,000 people.

According to figures reported by Congolese authorities and cited by Al Jazeera, 9,066 people have tested positive and 4,381 have died, a case-fatality rate of roughly 48 percent. The toll has climbed steeply in recent weeks: a World Health Organization situation report put the cumulative count at 7,890 confirmed cases and 3,799 deaths as of September 23, meaning more than 1,100 new infections and over 580 additional deaths have been logged in the three weeks since. The outbreak has now spread across seven of Congo's 26 provinces, with Ituri and North Kivu bearing the brunt of transmission. As of the WHO's September count, responders had traced more than 32,000 contacts of known patients and managed to follow up with over 80 percent of them within the required 24-hour window, while nearly 2,000 patients had recovered and been discharged from isolation.

A disease outrunning the response

The epidemic, caused by the Bundibugyo strain of Ebola virus, was declared by Congo's health ministry on May 15 after a cluster of cases emerged in Ituri province. Unlike the Zaire strain responsible for most previous outbreaks — including the 2018-2020 Kivu epidemic, the second-largest until this one overtook it — Bundibugyo has no vaccine or treatment approved specifically against it. The licensed vaccine Ervebo, widely used in earlier Congolese outbreaks, protects only against the Zaire strain.

The WHO declared the outbreak a public health emergency of international concern in mid-May, and the Africa Centres for Disease Control and Prevention separately classified it a continental public health emergency. The two agencies subsequently launched a response and preparedness plan for Congo and Uganda valued at roughly half a billion dollars, with donor governments pledging close to that sum at a ministerial meeting in Kampala by midyear. Africa CDC's director-general, Jean Kaseya, has repeatedly cautioned that the official tally likely understates the epidemic's true size, given how much of the transmission is occurring in rural areas with little surveillance capacity and in communities that bury the dead without reporting deaths to authorities.

Despite that mobilisation, the virus has spread faster than any prior Ebola outbreak in Congo's history. It took only about 40 days from the start of the response for confirmed cases to pass 1,000, compared with roughly 235 days during the 2018-2020 outbreak. The virus has since crossed borders. Uganda recorded 20 cases and two deaths before being declared Ebola-free in August, and a single imported case in France recovered without further transmission. Kenya reported its first case, and its first Ebola death, in the past two weeks: a Kenyan national who had lived in Congo for several years fell ill after travelling overland through Uganda to Nairobi, where he died on October 5, according to reporting on the case. Dozens of his contacts, including fellow passengers on his flight, were placed under monitoring.

Conflict and mistrust complicate containment

The provinces at the centre of the outbreak, Ituri and North Kivu, are also the epicentre of Congo's long-running conflict with the M23 rebel movement, which controls swaths of territory in the east. Humanitarian officials have said fighting and insecurity have repeatedly interrupted contact tracing and the movement of medical supplies into affected health zones, allowing chains of transmission to go undetected for longer.

The toll on responders has been severe. The Africa CDC has said more than 50 health workers have died since the outbreak began, and the WHO warned last month that Congo was running short of trained staff willing to work in isolation wards, a shortage compounded by strikes over unpaid wages. Mistrust of the response has, in places, turned violent. In late September, a local official in Butembo, a North Kivu city at the heart of the outbreak, was beaten to death at his home after urging residents on a radio programme to take Ebola prevention measures seriously, according to his political party. Separately, armed men attacked a handwashing checkpoint in nearby Beni territory, killing at least one person. Attribution for the attacks was not immediately established in either case, but officials and aid workers in the region have repeatedly pointed to misinformation and suspicion of outside responders as recurring drivers of violence against the Ebola effort.

"The continuously high crude case fatality ratio" and the high rate of deaths occurring in the community, rather than in treatment centres, "highlights the seriousness of the disease and the persistent challenges in timely case detection," the World Health Organization said in a situation report cited in wire coverage of the outbreak last month.

The WHO's current risk assessment rates the threat inside Congo as very high, the risk to countries sharing a land border as high, and the risk to the rest of Africa and the world as low. The agency has advised against any restriction on travel or trade with the affected countries, a recommendation it says it will continue to monitor.

A race to find a vaccine

With no approved countermeasure against the Bundibugyo strain, the response has leaned heavily on untested candidate vaccines. The University of Oxford began the first human trial of a candidate vaccine, ChAdOx1 BDBV, in Britain in July, backed by funding from the Coalition for Epidemic Preparedness Innovations. Early-stage human testing of that vaccine expanded to Uganda on October 6, and a separate Moderna-developed candidate received ethical clearance for similar trials in Uganda the following day. The Serum Institute of India has already manufactured roughly 620,000 doses of the Oxford candidate in anticipation of a positive result, though none has yet been proven effective against this strain. A separate trial combining an experimental monoclonal antibody treatment with the antiviral remdesivir began enrolling patients in Congo in July.

The WHO's health emergencies chief, Dr Chikwe Ihekweazu, said on Tuesday that a trial specifically designed to measure vaccine efficacy against the Bundibugyo strain is being prepared for Congo in the coming weeks, a step officials hope could finally give responders a tool beyond isolation, contact tracing and supportive care, the methods that have so far failed to bring the epidemic under control.

For now, the outbreak's trajectory remains the central concern. Case numbers have fluctuated by province in recent weeks, falling in parts of Ituri while rising in North Kivu, where the fatality rate has been markedly higher than elsewhere. With the virus already established in seven provinces and cases having reached three other countries, health officials say the coming weeks will determine whether Congo's seventeenth recorded Ebola outbreak overtakes the West African epidemic as the deadliest in history, or whether the scaled-up international response finally slows its spread.