DR Congo launches Ebola vaccine trial as Bundibugyo outbreak surpasses 9,500 cases

The Democratic Republic of Congo has launched the first clinical trial aimed at finding vaccine protection against the Bundibugyo species of Ebola, with the first participants vaccinated in the eastern city of Bunia on October 23, according to the World Health Organization. WHO Director-General Tedros Adhanom Ghebreyesus announced the start of the study on X, calling it the Tumaini trial. Tumaini means “hope” in Swahili.

He said the trial was a DRC-led effort supported by WHO to determine whether vaccine candidates designed for Bundibugyo virus can protect people at risk. The trial begins during what the reports describe as the DRC’s largest recorded Bundibugyo outbreak. Channels Television said the epidemic had passed 9,700 cases and caused more than 4,600 deaths.

Premium Times, citing figures available on October 21 from organisations supporting the trial, reported 9,552 confirmed cases and 4,602 deaths. The difference in totals appears to reflect the dates and reporting points used by the two accounts. Both portray the outbreak as severe and emphasise the lack of an approved vaccine or treatment specifically for Bundibugyo virus.

The study will test Ervebo, a vaccine licensed for Ebola disease caused by the more common Zaire species. Its effectiveness against Bundibugyo has not been established in humans, although Premium Times said laboratory and animal findings had raised the possibility of cross-protection. Tumaini is described as a Phase II/III study using an adaptive platform design.

That structure allows several vaccine candidates to be assessed within one trial rather than through entirely separate studies. The research will also use ring vaccination, focusing on contacts of confirmed cases and other people considered at high risk. Two vaccines developed specifically for Bundibugyo are expected to join the study.

One is an Oxford candidate using a ChAdOx1 adenoviral vector, developed with the Serum Institute of India; the other is being developed by Moderna using mRNA technology. Both are at earlier stages of development, according to the reports. The trial is co-led and co-sponsored by the DRC’s Institut National de Recherche Biomédicale and the University of Antwerp’s Global Health Institute, with the Congolese Health Ministry providing national leadership.

WHO is supplying technical and scientific advice, while the Coalition for Epidemic Preparedness Innovations is providing funding and operational support. The launch follows earlier work examining whether existing Ebola vaccines might generate immune responses against Bundibugyo. Premium Times reported that the DRC had received an initial allocation of 70,000 Ervebo doses, including 20,000 intended for a clinical trial and 50,000 for frontline and health workers.

The new study is intended to provide evidence on safety, immune response and effectiveness while the outbreak continues.