The Ebola Bundibugyo virus (BDBV) outbreak in the Democratic Republic of Congo and Uganda has reached 837 confirmed cases in DRC as of the most recent situation report from the European Centre for Disease Prevention and Control (ECDC), according to data published in ECDC’s Week 25 (2026) rapid risk assessment; Uganda has reported additional confirmed cases separately (approximately 19 as of the preceding WHO DON). The WHO Disease Outbreak Notice 608 (WHO-DON608-2026), issued June 18, confirms the outbreak remains active across multiple health zones in eastern DRC and the cross-border region of Uganda.
The World Health Organization’s International Health Regulations Emergency Committee declared a Public Health Emergency of International Concern (PHEIC) on May 17, 2026. The IHR Emergency Committee first met on May 19, 2026; temporary recommendations were issued on May 22, 2026. The second scheduled review falls within 90 days of that initial meeting.
No licensed vaccine for BDBV
No vaccine licensed specifically for the Bundibugyo strain of Ebola virus disease is currently available. The licensed Ebola vaccines — Ervebo (rVSV-ZEBOV, Merck) and the two-dose Zabdeno/Mvabea regimen (Johnson & Johnson) — target the Zaire strain (EBOV). Both are ineffective against BDBV because the viral surface glycoprotein, the primary vaccine antigen, differs substantially between strains. Cross-protection has not been established.
The only BDBV-specific candidate in human testing is VSV-BDBV, a vesicular stomatitis virus vector analogous to Ervebo but encoding the Bundibugyo glycoprotein. Phase I data are limited; no Phase 2 or 3 efficacy data exist. Investigational ring vaccination protocols using VSV-BDBV were assessed at the time the PHEIC was declared; uptake and outcomes have not been publicly reported.
Outbreak context
The BDBV strain was first identified in Bundibugyo District, Uganda, in 2007 (approximately 56 laboratory-confirmed cases out of approximately 149 suspected cases total, with 37 deaths; CFR approximately 25%). A second outbreak occurred in DRC’s Isiro, Orientale Province, in 2012 (approximately 57 confirmed cases, approximately 25–34 deaths). The current outbreak represents the largest BDBV event in recorded history by confirmed case count.
Case fatality rates in prior BDBV outbreaks ranged from approximately 25% (2007 Uganda) to approximately 50% (2012 DRC Isiro). The WHO has not published a case fatality rate for the current outbreak in the public DON.
Case management relies on supportive care and experimental therapeutics evaluated under compassionate use or expanded access protocols. The monoclonal antibody cocktail Inmazeb (atoltivimab, maftivimab, odesivimab-ebgn), licensed in the United States for Zaire EBOV, has binding affinity for BDBV glycoprotein, but clinical data in BDBV-infected patients are limited.
Correction (2026-06-19): Four errors corrected by post-publication fact-check. (1) The 2007 Uganda BDBV outbreak was reported as “186 confirmed cases”; primary literature and CDC/WHO records consistently cite approximately 56 laboratory-confirmed cases (approximately 149 suspected/putative total); the figure 186 does not correspond to any recognised case classification for that outbreak. (2) The 837-case figure reflects DRC-confirmed cases as reported in the ECDC Week 25 data; Uganda had approximately 19 additional confirmed cases separately — the article now clarifies the geographic attribution. (3) The IHR Emergency Committee was said to have “convened for the first time on May 22”; the committee first met May 19, 2026, and May 22 is when temporary recommendations were issued. (4) The 2012 DRC Isiro outbreak deaths were stated as 36; sources variously cite 25–34 deaths; the article has been corrected to reflect the range. The CFR range for prior outbreaks has also been corrected: the 2012 DRC outbreak CFR was approximately 50%, not capped at 34%.