The World Health Organisation (WHO) has issued new emergency guidance on using the licensed Ervebo vaccine during outbreaks of Bundibugyo virus disease, now limiting its use to research protocols.

The organisation made this known in a statement on Tuesday, saying the guidance followed an extraordinary meeting of the Strategic Advisory Group of Experts on Immunisation held on August 19, 2026.

The organisation said Ervebo should currently be used against Bundibugyo virus only within a research protocol to generate evidence on its effectiveness, rather than through broader routine outbreak vaccination.

According to the WHO, a ring vaccination randomised controlled trial would be the most robust approach for determining Ervebo’s efficacy against Bundibugyo virus disease among affected populations.

The organisation said broader vaccine use before trial results would require a comprehensive risk-mitigation plan addressing potential risks associated with such use during outbreak response and promptly monitoring recipient health outcomes.

“WHO continues recommending preventive Ervebo vaccination for healthcare and frontline workers in Ebola virus priority areas with previous Ebola disease outbreaks,” the organisation said.

The organisation also emphasised preventive vaccination policy in its guidance.

“In areas affected by the current Bundibugyo outbreak, Ervebo should only support outbreak response through research protocols, including ring trials or observational vaccine-effectiveness studies.” WHO said, stressing evidence generation remains essential.

“Such studies could provide additional evidence about the potential performance of Ervebo against Bundibugyo virus during ongoing outbreaks,” it added.

The statement said those findings could later inform future policy and vaccine recommendations.

The organisation said off-label use might be considered in exceptional cases where research was not feasible, provided reliable vaccination records could track recipients and subsequent health outcomes over time and support safety monitoring.

It urged accelerated development and rigorous evaluation of vaccines specifically targeting Bundibugyo virus disease and post-exposure prophylaxis products for outbreak preparedness and response, as well as other needed countermeasures for affected populations globally.

The organisation also called for stronger coordination among partners supporting the Democratic Republic of Congo and other countries considering Ervebo within research protocols to ensure consistent implementation and prompt evidence sharing.

It recommended developing and sharing master protocols for ring vaccination trials and high-quality observational studies to ensure timely, coordinated evidence generation during the outbreak and future emergency responses in affected countries.

(NAN)