Ebola: WHO launches first vaccine trial against the Bundibugyo strain in Bunia, over 4,600 dead in DRC

On October 23, 2026, the World Health Organization announced the launch of the first clinical vaccine trial against the Ebola epidemic currently striking the Democratic Republic of Congo. The first volunteers were vaccinated with Ervebo in Bunia, the capital of Ituri province and the epicenter of the outbreak, according to Al Jazeera, which cited a post by WHO Director-General Tedros Adhanom Ghebreyesus.

An existing vaccine against an orphan strain

Ervebo is approved for use against the Zaire strain of the virus. The trial aims to establish whether it also provides protection against the Bundibugyo strain, which is the source of the current epidemic and for which there is currently no approved vaccine or treatment. "This trial will help us understand" if candidates designed against Bundibugyo work, wrote Tedros Adhanom Ghebreyesus. The WHO's Director of Emergency Preparedness, Nigerian official Chikwe Ihekweazu, explains that the system was set up to produce the rigorous evidence required.

The protocol, named Tumaini, brings together several vaccine candidates within a single framework and is based on ring vaccination for the most exposed contacts. Two candidates specifically designed against Bundibugyo are expected to join the trial soon, according to the Coalition for Epidemic Preparedness Innovations (CEPI): a ChAdOx1 adenoviral vector vaccine from the University of Oxford and a messenger RNA vaccine from Moderna. Pregnant women and children aged 12 and over are included in the trial.

The deadliest in Congolese history

Declared in May 2026, this is the seventeenth Ebola epidemic in the DRC and the most severe ever recorded in the country: more than 9,700 cases and over 4,600 deaths, according to figures reported by Al Jazeera. The WHO has declared a public health emergency of international concern, its second-highest alert level. In August 2026, the organization indicated that 70,000 doses of Ervebo had been approved for the DRC, with approximately 50,000 intended for healthcare workers and frontline staff and 20,000 for the clinical trial, according to Africanews.

Four countries affected, a continental record

The epidemic has spread to four countries in East, Central, and West Africa, marking the widest geographical reach ever attained by Ebola on the continent. Kenya has recorded nine cases since October 6, 2026, and announced a second death on October 23, stating it had "no evidence" of community transmission. On October 21, Nigeria confirmed an imported case of the Bundibugyo strain involving a diplomat who had traveled to Uganda, becoming the fourth country affected.

"We are facing a more complex epidemic landscape," said WHO Regional Director for Africa Mohamed Janabi on October 22, during an online press briefing reported by Africanews.

The comparison with the West African epidemic, which killed more than 11,000 people between late 2013 and 2016, haunts the continent's health authorities. The difference this time is that a vaccine trial is starting within the first months of the crisis and at the heart of the outbreak, rather than years later in laboratories in the North. It remains to be seen whether the supply of doses will keep pace with the spread.