Kenyan-Tested Ebola Vaccine Deployed to Combat Outbreak in DRC

The World Health Organization (WHO) and Africa Centres for Disease Control and Prevention (Africa CDC) have announced the release of 70,000 doses of the Ervebo Ebola vaccine to the Democratic Republic of Congo (DRC) amid its largest recorded Ebola outbreak.

Notably, this vaccine was tested on volunteers in Kenya over a decade ago, including early human trials conducted at the Kenya Medical Research Institute (KEMRI)-Wellcome Trust research centre in Kilifi. The initial trial in 2014 involved vaccinating 40 healthy adults, mostly health workers, to evaluate safety and immune response.

While Ervebo was originally developed from the rVSV-ZEBOV vaccine candidate and manufactured by Merck, Kenya played a key role in its early clinical testing alongside sites in Gabon, Switzerland, and Germany. The vaccine received WHO prequalification in 2019 for protection against the Zaire ebolavirus.

Current Outbreak Challenges

The ongoing outbreak in DRC is caused by the Bundibugyo virus, which differs from the Zaire strain targeted by Ervebo. No vaccine has yet been approved specifically for Bundibugyo virus disease, and it remains unclear if Ervebo offers protection against it. Early laboratory and animal studies suggest potential efficacy.

Of the 70,000 doses sent to DRC, 20,000 will be used in a Phase 3 clinical trial to assess vaccine effectiveness against Bundibugyo virus. The remaining 50,000 doses will be administered to frontline and health workers under WHO guidelines. Recipients will be fully informed about the vaccine’s unproven benefits against this strain and will provide informed consent.

Outbreak Scale and Response Funding

• As of August 12, 2026, the DRC has reported 4,665 confirmed cases and 2,184 deaths from Bundibugyo Ebola.
• The outbreak spans 54 health zones across six provinces, making it the deadliest Ebola outbreak recorded in the country.
• Uganda recently declared its outbreak over but remains at risk due to proximity to DRC.

Gavi, the Vaccine Alliance, is contributing US$7 million to fund the vaccine shipment and an additional US$6 million to sustain routine immunization services disrupted by the outbreak. This support includes maintaining vaccinations for over 1.17 million children under two years old in affected provinces, protecting them from diseases like measles.

Kenya’s Role and Future Prospects

Kenya’s involvement in the early testing of Ervebo underscores its contribution to combating deadly diseases in Africa. Since the establishment of the global Ebola vaccine stockpile, approximately 167,000 doses have been used in preventive campaigns across several African countries, including Kenya.

The Phase 3 trial in DRC is expected to provide critical data on whether Ervebo can effectively protect against the Bundibugyo virus, potentially expanding vaccine options for future outbreaks.