Two new Ebola vaccine candidates will be added to an ongoing clinical trial in the Democratic Republic of the Congo (DRC), where authorities continue to battle a deadly outbreak caused by the Bundibugyo species of the virus, according to a press release by the World Health Organization (WHO). The announcement follows the recommendation of WHO’s independent Technical Advisory Group on Candidate Vaccines Prioritization. The addition marks the first time that vaccines specifically designed for the Bundibugyo virus will be evaluated during an outbreak of the disease. The two candidates are ChAdOx1 and mRNA-1469. Both will be integrated into the Tumaini multi-vaccine trial following national approvals.
ChAdOx1 was developed by the University of Oxford with the Serum Institute of India, while mRNA-1469 was developed by the American pharmaceutical and biotech company Moderna. WHO convened the expert group that recommended them this week for further clinical evaluation, based on available evidence. The DRC has been battling the deadly outbreak of Ebola disease caused by the rare Bundibugyo virus species for nearly six months. It has become the largest outbreak in the country’s history. As of 1 November, there were more than 10,500 confirmed cases and 5,126 deaths.
WHO is supporting the Tumaini multi-vaccine trial, named after the Swahili word for “hope”. It was launched on 23 October in the eastern city of Bunia, capital of Ituri province, which remains the epicentre of the outbreak. The Ervebo vaccine, used to treat the Zaire species of the Ebola virus, is already being tested to determine whether it is effective against the Bundibugyo species. The two new vaccine candidates will enter the trial following national approvals. Tumaini is designed to test multiple vaccine candidates within a single trial.
The trial uses a ring-vaccination approach that focuses on contacts of people with confirmed Ebola Bundibugyo. WHO and partners pioneered the strategy during the West Africa Ebola outbreak a decade ago, where a trial in Guinea established the efficacy of the Ervebo vaccine.
“The fact that these vaccines are ready to enter clinical trials is a testament to the power of science and partnership,” said WHO Director-General Tedros Adhanom Ghebreyesus.
He stressed that while vaccines alone will not end the outbreak, “they could become a powerful new tool for bringing it under control”. The remark underscored the role of the new candidates alongside wider response efforts.
Four vaccination rings have been set up and several more are being prepared. Research into other potential treatments is also moving forward. The expanded trial will allow scientists to assess multiple candidates in parallel against the Bundibugyo species. WHO continues to coordinate with national authorities and partners supporting the response. The agency signaled that further progress will depend on national approvals and the evolution of the outbreak.