The World Health Organisation (WHO) has launched a clinical trial in the Democratic Republic of the Congo (DR Congo) to determine whether vaccine candidates can protect people against the Bundibugyo strain of Ebola, as health authorities intensify efforts to control an outbreak that has killed thousands.
The trial, called Tumaini, meaning “hope” in Swahili, began on Friday, October 23, 2026, when the first participant received a vaccine in Bunia, the capital of Ituri province in eastern DR Congo. Researchers will assess the safety, immune response and effectiveness of different vaccine candidates, with the aim of finding reliable protection against a strain for which no vaccine has been approved.
The initiative marks an important step in the fight against the current outbreak, while offering scientists an opportunity to strengthen preparations for future emergencies involving the virus.
WHO Ebola Vaccine Trial in DR Congo Tests Multiple Candidates
The trial began with Ervebo, a vaccine already licensed to prevent Ebola disease caused by the Zaire strain. However, researchers have not established whether the vaccine can provide effective protection against the Bundibugyo strain responsible for the current outbreak.
Scientists will therefore examine its performance under a clinical research programme designed to generate evidence about its safety and effectiveness against the virus.
Two additional vaccine candidates are expected to join the study. One is being developed by Moderna, while the other comes from the University of Oxford in collaboration with the Serum Institute of India. Both candidates are specifically being developed to target the Bundibugyo virus and have received support from the Coalition for Epidemic Preparedness Innovations.
The study uses an adaptive platform design, allowing researchers to assess several candidates within a single trial framework rather than conducting entirely separate studies for each vaccine. This approach could help scientists gather evidence more efficiently during an active outbreak.
Researchers will also use a ring vaccination strategy, which focuses on contacts of confirmed Ebola patients and other people considered at high risk of infection. By concentrating on these groups, the study aims to evaluate potential protection while supporting wider efforts to interrupt transmission.
Outbreak Highlights the Need for Targeted Protection
The trial began as DR Congo continued to face a major public health emergency. Figures released by organisations supporting the research showed that the country had recorded 9,552 confirmed cases and 4,602 deaths as of October 21, 2026. <escape>[2]</escape>
The scale of the outbreak has increased pressure on health authorities to improve surveillance, identify infections quickly and strengthen the tools available to protect vulnerable communities.
One major challenge is the absence of an approved vaccine specifically targeting the Bundibugyo strain. Although vaccines exist for other forms of Ebola, their effectiveness cannot automatically be assumed to extend to this distinct virus.
The WHO-backed research could help close this gap by establishing whether the candidates provide meaningful protection. The findings may also guide future vaccine development and help health agencies respond more effectively when similar outbreaks occur.
However, the launch of the trial does not mean scientists have already confirmed that any candidate can prevent Bundibugyo infections. Researchers must evaluate the results carefully before drawing conclusions about effectiveness or recommending wider use.
What the Trial Could Mean for Future Outbreaks
The Tumaini trial is being led by Congolese health authorities and research institutions, with support from the WHO and international partners. Its findings could contribute to the ongoing response while improving scientific understanding of how to prevent future outbreaks.
Beyond the immediate crisis, the research may help health officials make better-informed decisions about vaccination strategies, emergency planning and the protection of people exposed to the virus.
For now, surveillance, contact tracing, infection prevention and public awareness remain essential parts of the response. The vaccine trial adds another potential tool, but its ultimate value will depend on the evidence researchers produce.
If the candidates demonstrate adequate safety and protection, the study could represent a significant advance in preparedness against the Bundibugyo strain. Until then, health authorities must continue combining established outbreak-control measures with carefully monitored scientific research.
