DRC Ebola Outbreak Caused by a Virus Species With Uncertain Vaccine Coverage

The DRC's 2026 Ebola outbreak — 3,973 cases, 1,801 deaths as of 4 August across 51 health zones — is driven by the Bundibugyo virus species, not the Zaire strain behind most DRC outbreaks. Licensed vaccines were validated against Zaire, leaving their efficacy against Bundibugyo uncertain. Responders face this gap in a conflict zone with cross-border spread into Uganda.