WHO Expert Panel: Ervebo Ring Vaccination Halted for BDBV — ChAdOx1 BDBV, MBP134, and Remdesivir Prioritized for Clinical Trials

On 28 May 2026, WHO convened an expert panel from its R&D Blueprint and SAGE advisory groups, joined by representatives of the DRC and Uganda governments, Africa CDC, ANRS (France), and international scientific partners, to evaluate candidate treatments and vaccines for Bundibugyo virus disease. The panel issued a landmark recommendation that rVSV-ZEBOV (Ervebo) — currently deployed off-label in ring vaccination in the 2026 DRC-Uganda outbreak — should NOT be used outside research settings for BDBV efficacy assessment. This effectively ends the existing ring vaccination protocol as currently structured, restricting any Ervebo use to clinical trial settings only, reflecting that Ervebo is licensed only for Zaire ebolavirus and cross-protection against BDBV has not been demonstrated in humans. Among vaccine candidates, the panel prioritized: (1) ChAdOx1 BDBV (Oxford Jenner Institute / Serum Institute of India) — highest-priority candidate, additional animal data needed but could be ready for Phase 1 human trials within 2–3 months; (2) rVSV BDBV (IAVI) — 7–9 months before it is ready for assessment. Among therapeutics, the panel prioritized for clinical trials in confirmed cases: (3) MBP134 monoclonal antibody cocktail; (4) Maftivimab® monoclonal antibody; and (5) remdesivir antiviral. Obeldesivir, an oral antiviral prodrug, was recommended for evaluation as post-exposure prophylaxis for contacts. The WHO statement stipulated that all candidate products must be used 'exclusively within clinical trials to generate robust data,' reflecting the absence of any licensed or empirically validated BDBV-specific treatment or vaccine after 50 years of periodic outbreaks.