The World Health Organisation (WHO) has cautioned against assuming that Ervebo®, the only licensed Ebola vaccine, can protect people against the Bundibugyo virus (BDBV), amid the ongoing outbreak.

In its updated emergency guidance, WHO said available animal, immunological and observational evidence suggests the vaccine may offer some cross-protection against Bundibugyo virus (BDBV). However, the evidence remains insufficient to establish whether Ervebo® provides meaningful protection against the virus in humans.

WHO recommends that any use of Ervebo® against BDBV be carried out only under research protocols, particularly through a ring randomised controlled trial aimed at generating reliable efficacy data. The agency also stressed that proven outbreak-control measures should continue while research is ongoing.

The WHO further called for clear communication about the vaccine’s uncertain effectiveness against BDBV and urged faster development of BDBV-specific vaccines and other countermeasures.