WHO Begins Ebola Vaccine Trial in DR Congo

The World Health Organisation (WHO) has announced the start of a clinical trial to evaluate Ebola vaccines during the ongoing outbreak in the Democratic Republic of Congo (DR Congo).

The trial, known as Tumaini, meaning “hope” in Swahili, began on Friday, October 23, with the first participants receiving the Ervebo vaccine in Bunia, the capital of Ituri province, one of the areas at the centre of the outbreak.

WHO Director-General Tedros Adhanom Ghebreyesus announced the development, saying the study would help determine whether available vaccine candidates could protect against the Bundibugyo strain of Ebola.

Unlike the more common Zaire strain, the Bundibugyo strain responsible for the current outbreak has no approved vaccine. Ervebo is licensed to prevent disease caused by the Zaire strain, but researchers will now investigate whether it offers any protection against Bundibugyo.

The adaptive clinical trial is designed to assess the safety, immune response and effectiveness of multiple vaccine candidates within a single research framework. It will use a ring vaccination approach, targeting contacts of confirmed cases and other people considered at high risk of infection.

Two additional candidates are expected to join the trial. They are being developed by Moderna and the University of Oxford in collaboration with the Serum Institute of India.

The study is being led by Congolese health authorities and research institutions, with technical and operational support from WHO and international partners, including the Coalition for Epidemic Preparedness Innovations.

According to figures released by organisations supporting the trial, DR Congo had recorded 9,552 cases and 4,602 deaths as of October 21, 2026.

The outbreak, declared on May 15, prompted WHO to declare a Public Health Emergency of International Concern.

The start of the trial marks a significant step in efforts to develop protection against the Bundibugyo strain. However, researchers must establish whether the vaccine candidates are safe and effective before their use can be recommended for this strain.