WHO clears trials of two Ebola vaccines built for Bundibugyo strain

The World Health Organization (WHO) has given the go-ahead for clinical trials of two Ebola vaccines developed specifically to target the Bundibugyo strain, the virus behind an outbreak in the Democratic Republic of the Congo (DRC) that has killed more than 5,300 people.

WHO Director-General Tedros Adhanom Ghebreyesus announced the decision at a news conference in Geneva. He said the agency's expert groups had backed adding the two candidates on Monday.

The trials will take place in the DRC and will be run by the country's National Institute for Biomedical Research, with WHO and partner organisations sponsoring the work.

Why this matters

The two vaccines are ChAdOx1 BDBV, developed by the University of Oxford with the Serum Institute of India, and mRNA-1469 from Moderna.

Until now, no vaccine or treatment had been designed specifically for Bundibugyo, which kills about half of those it infects. The only trial running since last month has used Ervebo, a vaccine made for the Zaire strain.

For Nigerians, the outbreak is not a distant story. The Africa CDC says 10,444 Bundibugyo cases have been confirmed, mostly in the DRC. Kenya has reported nine cases, including two deaths, and Nigeria has recorded one case.

A single case in Nigeria is a reminder that infectious disease can travel quickly across borders, and that having a vaccine matched to the circulating strain is a public health priority.

Separately, a British healthcare worker who caught Ebola is being moved from the DRC to the United Kingdom for specialist treatment.

What happens next

The trials are expected to produce results in early 2027. If the vaccines prove safe and effective, they could give health authorities a tool built for this strain rather than borrowed from the fight against Zaire Ebola.

Until then, the response in the DRC and neighbouring countries will rely on surveillance, contact tracing and the existing Zaire vaccine.