The fight against Ebola in the Democratic Republic of Congo (DRC) could be entering a new phase, with two experimental vaccines set to undergo further evaluation as part of an ongoing clinical trial.
The World Health Organization (WHO) has recommended adding ChAdOx1 and mRNA-1469 to the Tumaini trial, marking a significant development in efforts to find vaccines specifically targeting the Bundibugyo virus.
The two candidates were developed by the University of Oxford in partnership with the Serum Institute of India, and by US biotechnology company Moderna, respectively.
Unlike existing Ebola vaccines primarily designed to protect against the Zaire strain, these candidates were developed to target Bundibugyo, the virus responsible for the current outbreak.
However, their inclusion in the research programme does not mean they are already approved or proven to be effective. Further evaluation and national regulatory authorisation are required before the trials can begin.
International research effort
The WHO's recommendation followed a review of available scientific evidence, including preclinical and clinical data. Manufacturers were informed of the decision on 2 November.
WHO Director-General Tedros Adhanom Ghebreyesus described the development as an example of what scientific research and international collaboration can achieve during a public health emergency.
He also recognised the contributions of researchers, healthcare workers and volunteers supporting the response.
The trial is coordinated by the DRC's National Institute for Biomedical Research (INRB), working with Congolese and international partners. These include the University of Antwerp, Médecins Sans Frontières, Epicentre and the Africa Centres for Disease Control and Prevention.
The Coalition for Epidemic Preparedness Innovations (CEPI) is also supporting efforts to accelerate the development of vaccines and other medical interventions.
How the Tumaini trial works
Tumaini, a Swahili word meaning "hope", uses a ring vaccination approach. Under this strategy, people who have been in contact with confirmed Ebola patients, together with others at risk around them, are offered vaccination to help interrupt transmission.
Four vaccination networks are already operating, with additional networks being prepared.
Researchers are also examining whether Ervebo, a vaccine licensed against the Zaire ebolavirus, could offer protection against Bundibugyo.
Its effectiveness against this strain has not yet been established, and it should not be regarded as an approved Bundibugyo vaccine.
Treatment research continues
Vaccination is only one part of the wider response. Researchers are also investigating possible treatments through the PARTNERS trial, launched in July.
The study is examining MBP134, remdesivir and the potential benefits of using the two treatments together. Maftivimab is also expected to be added to the research programme.
Separately, scientists are studying obeldevisir as a possible intervention for people who have been exposed to the virus, with the aim of assessing whether it could help prevent infection.
The first findings from the therapeutic research are expected in the coming months, while initial conclusions from the vaccine trials are anticipated in early 2027.
Difficult conditions complicate the response
The scientific advances come as health authorities face significant operational challenges in eastern DRC, where the outbreak was declared on 15 May 2026.
Insecurity, restricted access to affected communities and mistrust of some health facilities have made it harder for response teams to reach people who need assistance.
The reported detection of cases in other countries, including Kenya and Nigeria, has also heightened concern about the possibility of wider regional spread. Such reports require careful monitoring and confirmation by public health authorities.
Although the two new vaccine candidates have yet to demonstrate their effectiveness, their evaluation represents an important development in the search for protection against a strain for which no licensed vaccine is currently available.
For communities affected by the outbreak, the challenge now is to turn scientific progress into practical protection through research, accessible healthcare, community engagement and effective disease surveillance.
