DRC's Bundibugyo outbreak is second-largest on record, and no licensed vaccine exists

The Democratic Republic of the Congo declared a Bundibugyo virus outbreak on May 15, 2026, initially centered in Ituri province. As of October 15, the CDC reported 9,235 confirmed cases and 4,444 confirmed deaths, with the DRC accounting for 9,212 cases and 4,441 deaths. It is the second-largest Ebola outbreak on record.

It is also spreading far faster than past outbreaks. The outbreak surpassed 1,000 confirmed cases within 40 days of response activation, compared with roughly 235 days in the 2018 DRC outbreak.

Cases have been confirmed in seven DRC provinces: Bas-Uele, Haut-Uele, Ituri, Nord-Kivu, Sud-Kivu, Sud-Ubangi, and Tshopo. Health officials have reported cases in an eighth province, North Ubangi, though the DRC has not officially announced those infections. Kenya has confirmed seven cases, including three health workers who treated the country's first patient and a relative of that patient.

Ten students in the DRC have died of the virus since schools reopened about a month earlier.

The response is complicated by a gap in the toolset. No vaccine or therapeutic is licensed specifically for Bundibugyo. On Friday, frontline workers in Beni received the Ervebo vaccine under a compassionate-use program. Ervebo targets the Zaire strain. Health authorities have said it could offer some protection because the two viruses are related, but whether it prevents illness in people infected with Bundibugyo is still being studied.

What is clear is the trajectory. The geographic spread — seven confirmed provinces, an eighth reported, and cross-border transmission into Kenya — reflects a response under strain.

For readers in the United States, the immediate risk remains low. No cases linked to this outbreak have been confirmed in the US, and the CDC rates the risk to the American public as low. The practical takeaway is not personal alarm but attention to the vaccine question: if Ervebo does not cross-protect against Bundibugyo, the response is relying on a tool whose value is unproven, and the outbreak's course will depend on containment measures that have already been outpaced once.