A landmark Phase 2/3 clinical trial to evaluate vaccines against the Bundibugyo Ebola virus was launched on Friday, 23 October 2026, in Bunia, the capital of the hardest-hit Ituri Province in eastern Democratic Republic of the Congo (DRC). The trial, named Tumaini — meaning 'hope' in Swahili — comes as the DRC battles its largest and deadliest recorded Ebola outbreak, with the country having logged 9,704 confirmed cases and 4,687 deaths as of 20 October, according to DRC health authorities.

What the Tumaini Trial Involves

The trial is funded and supported by the Coalition for Epidemic Preparedness Innovations (CEPI) and employs an adaptive platform design, enabling multiple vaccine candidates to be assessed within a single study. It uses a ring vaccination approach, targeting individuals who have been in direct contact with confirmed Ebola patients and therefore face a significantly elevated risk of infection.

The first vaccine entering the trial is Ervebo, already licensed for prevention of disease caused by the Zaire Ebola virus, though it has not been proven effective against the Bundibugyo strain. Two additional candidates developed specifically against the Bundibugyo virus — one by Moderna and another by the University of Oxford in collaboration with the Serum Institute of India — are expected to join the trial 'shortly,' according to CEPI.

Why No Approved Vaccine Exists Yet

Despite the DRC suffering repeated and devastating Ebola outbreaks over decades, no vaccine has yet been approved specifically against the Bundibugyo Ebola virus. The Bundibugyo strain, first identified in Uganda in 2007, is distinct from the Zaire strain, against which Ervebo provides protection. This gap has left frontline health workers and high-risk communities without a proven targeted shield — a vulnerability that the Tumaini trial is designed to address.

Scale of the Current Outbreak

The epidemic was officially declared in the DRC on 15 May and was designated a public health emergency of international concern by the World Health Organisation (WHO) just two days later. The Africa CDC subsequently declared it a public health emergency of continental security. The current outbreak has recorded a case fatality rate of 48.3% — among the highest seen in any major Ebola episode — and has surpassed all previous DRC outbreaks in scale. It now ranks as the second-largest Ebola outbreak globally, behind only the 2014–2016 West Africa epidemic which killed more than 11,000 people.

What Global Health Authorities Said

Chikwe Ihekweazu, Executive Director of the WHO's Health Emergencies Programme, said the launch 'marks a critical step towards establishing whether candidate vaccines can effectively protect people against the Bundibugyo virus.' Mohamed Janabi, WHO Regional Director for Africa, also welcomed the launch, stating that the trial would 'generate crucial evidence on candidate vaccines while strengthening the response to the ongoing outbreak and preparedness for future epidemics.'

What Happens Next

With Moderna and Oxford-Serum Institute candidates set to join the trial in the near term, researchers hope the adaptive design will allow faster head-to-head comparisons than traditional sequential trials. The DRC's health ministry, WHO, and CEPI are expected to provide regular updates on enrolment figures and early immunogenicity data. A proven Bundibugyo vaccine would mark a historic milestone in global epidemic preparedness — and could reshape how the world responds to Ebola variants beyond the dominant Zaire strain.