The World Health Organization (WHO) has officially approved clinical trials for two experimental vaccines targeting the Bundibugyo strain of the Ebola virus. This specific variant is currently driving a severe epidemic in the Democratic Republic of the Congo (DRC), where the outbreak has resulted in more than 5,300 deaths.
The newly approved candidates, ChAdOx1—developed by the University of Oxford in collaboration with the Serum Institute of India—and mRNA-1469, produced by the American pharmaceutical company Moderna, will be evaluated for the first time during an active outbreak. The decision follows a recommendation from a group of independent scientists who advised the World Health Organization based on positive preclinical test results.
Integration into Ongoing Research
Previously, these trials utilized Ervebo, a vaccine approved for the Zaire strain of Ebola. However, health officials have noted that while Ervebo has demonstrated efficacy against the Zaire variant, there is no certainty regarding its protection against the Bundibugyo strain currently circulating in the region.
“The fact that these vaccines are ready to enter clinical trials demonstrates the power of science and collaboration,” said WHO Director-General Tedros Adhanom Ghebreyesus. He cautioned, however, that vaccines are not a substitute for essential public health measures, including early care, contact tracing, isolation, and safe, dignified burials.
Next Steps for Vaccine Deployment
The inclusion of these two candidates in the field trials remains subject to final authorization by the relevant authorities in the DRC. According to the organization, preliminary results from the studies are expected by early 2027.
“We hope to obtain preliminary results by early 2027, which will allow us to realistically begin evaluating the possibilities of access to the vaccines once the trials are concluded, as well as their incorporation into response measures, with the goal of saving lives, slowing contagion and ending the epidemic in general,” said Meg Doherty, Director of the WHO Department of Regulation and Prequalification.
