Clinical trial begins in DR Congo to test Ebola vaccine against rare strain

UPDATE - follow-up to Ebola vaccine trial begins in DR Congo: The first clinical trial of an Ebola vaccine in the current DR Congo outbreak began on Friday, October 23, 2026. WHO chief Tedros Adhanom Ghebreyesus announced that the trial, named Tumaini, started with the first shot of the Ervebo vaccine administered in Bunia, the capital of Ituri province.

Outbreak Scale and Vaccine Challenge

The outbreak has passed 9,700 cases with deaths exceeding 4,600. The epidemic is driven by the Bundibugyo species of Ebola, for which no approved vaccines or treatments currently exist. Ervebo is an approved vaccine for the more common Zaire strain, and this full-scale human trial will test if it provides cross-protection against Bundibugyo.

Trial Details and Future Plans

The Tumaini trial uses a ring vaccination approach to immunise high-risk contacts. It will include pregnant women and children aged 12 and older, and will soon incorporate two Bundibugyo-specific candidate vaccines funded by the Coalition for Epidemic Preparedness Innovations. WHO emergencies director Chikwe Ihekweazu noted that success would provide the first clear evidence of vaccine efficacy against the Bundibugyo virus.

Context

Vaccine trials during active public health emergencies require careful coordination between international bodies like the WHO and local health authorities to protect vulnerable populations. Ring vaccination is a targeted strategy commonly used to contain infectious disease outbreaks by immunising the immediate contacts of infected individuals.