Advisory groups convened by the World Health Organization have considered promising candidates for prioritisation and evaluation in clinical trials, including a candidate vaccine ChAdOx1 Bundibugyo being developed by Oxford University/Serum Institute of India.

The vaccine could potentially become available within two to three months for efficacy assessment through a clinical trial, said the WHO.

Following the Ebola outbreak, the WHO said it was working with the governments of the Democratic Republic of the Congo (DRC) and Uganda — ground zero of the outbreak — to facilitate the of research evaluation of the identified products.

At present, there are no licensed therapeutics or vaccines approved for the prevention and treatment of the BVD (Bundibugyo virus disease).

For treatment, the experts recommended three candidate therapeutics for evaluation through clinical trials among confirmed BVD cases. They include the monoclonal antibodies MBP134 and Maftivimab (from US company Regeneron)as well as antiviral remdesivir (US company Gilead). Combination therapy using a monoclonal antibody and remdesivir is also recommended for evaluation, said the WHO.

Priority candidates

For post-exposure prophylaxis among contacts of confirmed and probable cases, the oral antiviral obeldesivir (Gilead) was identifies as a priority candidate, although experts noted that this approach depends on effective contact tracing, which remains operationally challenging in some of the affected areas of the DRC, said the WHO. “Research on post-exposure prophylaxis involves giving tablets of obeldesivir to contacts of cases to evaluate whether this prevents them from developing Ebola disease,” it said.

The most promising candidate vaccine was the single-dose rVSV Bundibugyo vaccine, being developed by the International AIDS Vaccine Initiative (IAVI). Its development would take about seven to nine months, said the WHO, before it is ready to be assessed through a clinical trial for its ability to prevent BDV.

Also on the radar is ChAdOx1 Bundibugyo — beingdeveloped by Oxford University/Serum Institute of India — with the potential to become available within three months for efficacy assessment through a clinical trial, it said. “However, additional animal data are still required to support and confirm further prioritization,” said the WHO, adding that a single-dose vaccine approach of this candidate could be suitable for contacts of Ebola cases, whereas a two-dose strategy might be considered for high-risk but unexposed populations such as health-care workers and frontline responders, it said.

Experts also looked at Ervebo (Merck MSD), the only licensed Ebola vaccine. It is approved for use during outbreaks caused by the most common Ebola virus in Africa, from the Orthoebolavirus family, said the WHO. Ervebo is not licensed for prevention of BVD and evidence on cross-protection to other Ebola virus species remains limited and inconclusive, the UN health agency said, adding that the WHO recommended Ervebo not be used outside carefully designed research settings to allow for its performance against BDV to be assessed.

Published on May 29, 2026