WHO-backed Tumaini trial starts vaccinating people against Bundibugyo Ebola in DR Congo

First doses in Bunia

The World Health Organization announced that the first clinical trial of an Ebola vaccine in the current outbreak has started in the Democratic Republic of Congo. Participants were vaccinated with the Ervebo vaccine in Bunia, the capital of northeastern Ituri province, which is the epicentre of the outbreak. WHO director-general Tedros Adhanom Ghebreyesus reported the start in a social media post on Friday, 23 October. The Coalition for Epidemic Preparedness Innovations (CEPI), which funds the study, described it as a phase 2/3 trial launched in Bunia.

The study is called Tumaini, which means hope in Swahili. It is designed as a single trial framework able to assess the safety, efficacy and immune response of several vaccines. It uses ring vaccination, in which people judged to be at high risk of infection from confirmed patients are immunised. Tedros said on X that the study will show whether any candidate vaccine for Bundibugyo works.

This trial will help us understand whether any of the vaccine candidates designed for Bundibugyo virus work.

The candidate vaccines

Ervebo is approved for the Zaire strain, the more common form of Ebola. Its protection against the Bundibugyo species has not yet been demonstrated, so the trial will test whether it offers cross-protection. No vaccine or treatment approved for Bundibugyo exists at present, according to the reports.

Two Bundibugyo-specific candidates are expected to join the trial shortly, CEPI said. One is a ChAdOx1 adenoviral vector vaccine developed at the University of Oxford in the United Kingdom, which Digi24 reports is being developed with the Serum Institute of India. The other, from the US-based Moderna group, uses messenger RNA technology. Both are now in earlier, smaller clinical trials, and both have received CEPI funding.

The trial will include pregnant women and children aged 12 years and older, groups that are often excluded from clinical trials. That is intended to generate evidence for these populations.

Outbreak scale and response

The DRC declared its 17th Ebola outbreak in May, which it describes as its worst ever. Since then more than 9,700 cases have been reported, and deaths have passed 4,600 in the latest figures. An earlier count published on Friday, 23 October, put deaths above 4,500.

The WHO responded by triggering a public health emergency of international concern, its second-highest alert level. The outbreak has now been reported in four countries across eastern, central and western Africa, the widest geographic spread of any Ebola outbreak on the continent to date.

Response statements and open questions

WHO emergencies director Chikwe Ihekweazu called the launch a crucial step toward establishing how well the candidate vaccines protect people. Mohamed Janabi, the WHO regional director for Africa, also welcomed the Friday launch, saying the study would generate crucial evidence while strengthening the response to the current outbreak and preparedness for future ones.

Steve Ahuka-Mundeke, a field manager in the Ebola response, described the study as an important step in meeting the urgent needs of affected communities.

Our priority is to stop the spread of the virus and save lives.

The reports do not give a date for the first results. According to CEPI, the two Bundibugyo candidates had not yet entered the trial as of Friday, 23 October, and were still expected to join shortly.