WHO Restricts Ervebo Vaccine Use as DRC Ebola Outbreak Drives New Research Strategy
Mirian Gom 
GENEVA, Switzerland – The World Health Organization (WHO) has issued fresh emergency guidance restricting the use of the licensed Ervebo Ebola vaccine during outbreaks of Bundibugyo virus disease (BVD) to approved research settings, as health authorities seek stronger scientific evidence on the vaccine’s effectiveness against the deadly strain.
The updated guidance followed an extraordinary meeting of the Strategic Advisory Group of Experts (SAGE) on Immunisation held on August 19, 2026, amid the ongoing Ebola outbreak in the Democratic Republic of the Congo (DRC).
According to WHO on Wednesday, Ervebo should no longer be deployed for broad outbreak vaccination against the Bundibugyo strain outside carefully monitored research programmes.
Instead, the organisation recommended that vaccination be carried out under ring vaccination randomised controlled trials, where close contacts of confirmed cases are immunised to generate reliable evidence on the vaccine’s protective effect.
WHO said expanding the vaccine’s use before scientific findings become available would require comprehensive risk-mitigation measures, including close monitoring of recipients and detailed safety assessments throughout the outbreak response.
The global health agency, however, maintained its existing recommendation for the preventive use of Ervebo among healthcare workers and frontline responders operating in Ebola-prone regions with previous outbreaks.
“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 stated.
It added that evidence generated from ongoing studies would help shape future vaccination policies and determine whether Ervebo can effectively protect against the Bundibugyo strain.
The organisation also noted that off-label use of the vaccine could only be considered in exceptional circumstances where research was not feasible, provided authorities maintained reliable vaccination records and monitored recipients for safety and effectiveness.
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