African health authorities are preparing to use a vaccine originally developed for the Zaire ebolavirus strain to combat the current Ebola outbreak in eastern Democratic Republic of Congo (DRC), which involves a different and rapidly spreading strain known as Bundibugyo.

Jean Kaseya, director general of the African Centres for Disease Control (Africa CDC), told reporters in a videoconference on Thursday, August 6th, 2026, that test cases indicate the vaccine has been effective in eliminating deaths, if not symptoms, among vaccinated individuals. "We saw zero deaths among people who are vaccinated," Kaseya said.

The outbreak has expanded significantly, with cases now reported in 51 health zones compared to just nine in May. Authorities estimate around 4,000 cases have been confirmed, up from 3,973 as of the latest data available on Tuesday.

Kaseya, speaking from Brazzaville in the neighboring Republic of Congo after meeting with World Health Organization (WHO) Director-General Tedros Adhanom Ghebreyesus in Kinshasa, emphasized the unprecedented severity of this Bundibugyo outbreak. He quoted Tedros: "It's time for the WHO and Africa CDC to conduct studies to check that there is no issue, additional issue, or maybe if the virus is not mutating, because the level of severity of this Bundibugyo outbreak is unprecedented."

The Africa CDC and WHO plan to launch research to investigate possible mutations or abnormalities in the virus, which is spreading six to eight times faster than any previous Ebola outbreak on record.

For context, during the most virulent and deadly Ebola outbreak on record—the Zaire strain outbreak in DRC between 2018 and 2020—one patient was identified from every 57 contacts at risk. That outbreak recorded 20 cases with only two deaths.

Sources