GHealth News – The World Health Organization (WHO) has recommended the inclusion of two additional vaccine candidates in an ongoing clinical trial in the Democratic Republic of the Congo (DRC), marking a significant step forward in efforts to combat the current Bundibugyo virus disease outbreak.
The candidates, ChAdOx1, developed through a collaboration between the University of Oxford and the Serum Institute of India, and Moderna’s mRNA-1469, are specifically designed to provide protection against Bundibugyo virus. They will become the first vaccines developed specifically for this Ebola virus species to undergo evaluation during an active outbreak.
The recommendation was issued by WHO’s independent Technical Advisory Group on Candidate Vaccines Prioritization, following an assessment of available preclinical and early clinical evidence. Both candidates are expected to enter the ongoing Tumaini clinical trial once the necessary national regulatory approvals have been secured.
Expanding the Tumaini vaccine trial
The Tumaini trial, led by the DRC’s National Institute of Biomedical Research (INRB), is designed to evaluate multiple vaccine candidates within a single study. It employs a ring-vaccination strategy, targeting contacts of individuals with confirmed Bundibugyo virus disease.
The approach builds on the experience gained during the 2014–2016 West Africa Ebola outbreak, when a landmark clinical trial in Guinea demonstrated the efficacy of Ervebo against Zaire ebolavirus.
Ervebo is already being evaluated in the Tumaini trial to assess its effectiveness against Bundibugyo virus, despite originally being developed to protect against a different Ebola virus species.
Four vaccination rings have already been established, with additional groups being prepared. These include contacts of individuals who have developed the disease or died from the infection.
The trial involves national and international partners, including the University of Antwerp, WHO, Epicentre, Médecins Sans Frontières (MSF), the Institute of Tropical Medicine in Antwerp and the Africa Centres for Disease Control and Prevention (Africa CDC). Funding and support for vaccine development have also been facilitated by the Coalition for Epidemic Preparedness Innovations (CEPI).
Treatment research progresses alongside vaccine development
Beyond vaccine research, clinical investigations into potential treatments for Bundibugyo virus disease are also progressing.
The WHO-sponsored PARTNERS trial, launched in July 2026, is assessing the potential benefits of three treatment approaches: the monoclonal antibody MBP134, the antiviral drug remdesivir, and a combination of both. The trial aims to determine whether these interventions can improve survival among patients with confirmed infection.
Maftivimab is also expected to be incorporated into the study to evaluate its potential as an additional treatment option. Separately, a post-exposure prophylaxis study investigating obeldevisir is underway.
Strengthening outbreak research and preparedness
WHO is supporting these investigations through its Research and Development Blueprint and Health Emergencies Programme, providing technical guidance, coordinating research partnerships and supporting the implementation of scientifically rigorous and ethically conducted studies during the outbreak response.
The inclusion of additional vaccine candidates and the expansion of treatment research reflect the importance of accelerating medical research during infectious disease emergencies, particularly when existing vaccines and therapeutics may not provide adequate protection against different viral species.
Initial findings from the treatment trials are expected in the coming months, while results from the Tumaini vaccine trial are anticipated in early 2027.
The findings could provide important evidence to guide future prevention and treatment strategies against Bundibugyo virus disease and strengthen preparedness for future Ebola outbreaks.
Source: World Health Organization (WHO)