The first participants in the Tumaini clinical trial — "hope" in Swahili — were vaccinated on Friday in Bunia, capital of Ituri province, in the east of the Democratic Republic of the Congo (DRC). It is the first attempt to measure, in the middle of an outbreak, whether any vaccine can protect against the Bundibugyo strain of the Ebola virus, for which no immuniser is approved.
The outbreak that has been spreading in the DRC since May is the largest and deadliest in the country's history and the second-largest ever recorded worldwide, behind only the West Africa epidemic of 2014 to 2016.
The outbreak in numbers
Congolese health authorities counted 9,704 confirmed cases and 4,687 deaths as of 20 October, with the data released on the evening of the preceding Wednesday. The case fatality rate stands at 48.3% — almost one death for every two confirmed cases.
The trial's sponsors released slightly different figures, of 9,552 cases and 4,602 deaths as of 21 October, a common discrepancy between tallies with different classification criteria and cut-off dates.
The outbreak was officially declared on 15 May 2026. Two days later, the World Health Organization (WHO) declared a public health emergency of international concern, and the Africa Centres for Disease Control and Prevention (Africa CDC) later declared a public health emergency of continental security. Ituri is the hardest-hit province.
How the trial works
Tumaini is a phase 2/3 study with an adaptive platform design: instead of one protocol per vaccine, a single protocol hosts several candidates, which can enter and leave as results come in. It is the format that makes it possible to test immunisers in the middle of an ongoing outbreak, when there is no time to set up a new study for each product.
The delivery strategy is ring vaccination, which immunises the contacts of confirmed cases and the people exposed around them — the group at highest risk of infection. The trial will assess safety, immune response and efficacy.
The first vaccine included is Ervebo, already licensed against the Zaire strain of Ebola but without proven efficacy against Bundibugyo. Candidates developed specifically against Bundibugyo by Moderna and by the University of Oxford, in partnership with the Serum Institute of India, are expected to join the study shortly. Those candidates are funded by the Coalition for Epidemic Preparedness Innovations (CEPI), which also supports the trial.
Who is running it
The study is co-sponsored and co-led by the DRC's Institut National de Recherche Biomédicale (INRB, National Institute of Biomedical Research) and the Global Health Institute of the University of Antwerp, in Belgium. National leadership rests with the Congolese health ministry, with a steering committee charged with aligning the trial with the outbreak response. The choice of which vaccines enter the platform is made independently by a WHO technical advisory group, and protocol adaptations must be validated by ACOREP, the Congolese regulatory authority.
What those in charge say
Chikwe Ihekweazu, executive director of the WHO Health Emergencies Programme, said the launch "marks a critical step towards establishing whether candidate vaccines can effectively protect people". Mohamed Janabi, WHO Regional Director for Africa, said the trial will produce "crucial evidence" on the candidates while strengthening the outbreak response and preparedness for the next ones.
Professor Steve Ahuka-Mundeke, who leads the field response in the DRC, welcomed the trial as "an important step towards meeting the urgent needs of affected communities" and added that the priority remains "to stop transmission and save lives", with the research coordinated with work on the ground.
With information from the Xinhua news agency, the Congolese outlet Actualite.cd and the World Health Organization.
