Ebola in DR Congo: outbreak nears a grim record as a vaccine stays months away

The ongoing Ebola outbreak in the Democratic Republic of Congo (DRC) has, by late July, edged to the brink of becoming the second-largest such outbreak on record. According to health ministry figures, confirmed cases have climbed into the thousands, putting the current outbreak within striking distance of the 2018-2020 Kivu outbreak in the country's east, which itself ranked as the second-largest Ebola outbreak ever recorded, behind only the 2014-2016 West Africa epidemic.

The current outbreak was officially declared the DRC's 17th Ebola outbreak on 15 May, with laboratory testing confirming the culprit as Bundibugyo virus — a less familiar but highly lethal species of Ebola virus. The outbreak quickly spread across the border into neighbouring Uganda.

Bundibugyo virus differs from the more widely known Zaire ebolavirus species. That distinction matters because the Ebola vaccines licensed for use worldwide, such as Ervebo, were developed specifically against the Zaire strain and offer no protection against Bundibugyo virus. Health officials describe that gap as one of the current outbreak's most consequential challenges.

Ebola disease spreads through direct contact with the bodily fluids of infected people or contaminated surfaces, and symptoms — which can include fever, severe headache, vomiting, diarrhoea and, in severe cases, uncontrolled bleeding — typically appear within two to twenty-one days of exposure. Health workers and family caregivers face the highest infection risk because of the close contact involved in treating the sick and preparing the dead for burial, which is why safe-burial teams have become a central pillar of outbreak response in the years since the West Africa epidemic a decade ago.

Past Bundibugyo virus outbreaks have carried case fatality rates ranging from roughly 30% to 50% — a range indicating that while supportive medical care is lifesaving, the disease itself remains extremely dangerous. Deaths reported so far in the DRC's current outbreak have tracked broadly in line with that historical range.

On 27 July, exactly 68 days after the World Health Organization declared the outbreak a public-health emergency of international concern, the first dose of an experimental vaccine was administered to a volunteer. Developed by the University of Oxford, the vaccine is the first candidate designed specifically to target Bundibugyo virus.

That milestone does not, however, mean a vaccine will be widely available soon. The Coalition for Epidemic Preparedness Innovations (CEPI) has announced $8.5 million in funding for Singapore-based Hilleman Laboratories to accelerate production of clinical-trial doses of the Bundibugyo vaccine. Manufacturing is expected to be complete by the end of the year, with human studies to follow.

That timeline creates a troubling gap against the outbreak's current trajectory: a proven, widely deployable vaccine sits months away, potentially arriving after the outbreak's peak has already passed.

There is a piece of encouraging news. Uganda's Ministry of Health declared its own outbreak over on 28 July, twelve days after the country's last confirmed case was discharged from care. Uganda reported a total of 20 confirmed cases and two deaths, a result health officials point to as evidence that rapid contact tracing and isolation measures can contain a limited spillover.

Whether the DRC achieves a similar outcome remains uncertain, health experts caution, because the outbreak continues to circulate actively in its source region — an area that is more densely populated and harder to reach than the areas affected in Uganda.

Experts stress that, in the near term, the most important tools are not a vaccine but rapid case detection, contact tracing, safe burial practices and community health communication aimed at building trust — measures presented as the most realistic way to slow the outbreak until a vaccine becomes available.