Two new Ebola vaccines to be tested in DR Congo trial

The World Health Organization has announced that two new Ebola vaccine candidates will be added to a clinical trial in the Democratic Republic of Congo. The trial aims to combat the ongoing outbreak caused by the rare Bundibugyo species of the Ebola virus. This development follows the recommendation of the WHO's independent Technical Advisory Group on Candidate Vaccines Prioritization. The vaccines are expected to provide a new tool in the fight against the disease.

The two vaccine candidates are ChAdOx1, developed by the University of Oxford with the Serum Institute of India, and mRNA-1469, developed by Moderna. According to WHO Director-General Tedros Adhanom Ghebreyesus, the fact that these vaccines are ready to enter clinical trials is a testament to the power of science and partnership. He stressed that while vaccines alone will not end the outbreak, they could become a powerful new tool for bringing it under control.

The DR Congo has been battling the Ebola outbreak for nearly six months, with over 10,500 confirmed cases and 5,126 deaths reported as of November 1, 2026. The outbreak is the largest in the country's history. The WHO is supporting the Tumaini multi-vaccine trial, which was launched on October 23 in the eastern city of Bunia. The trial aims to test multiple vaccine candidates within a single trial using a ring-vaccination approach.

The Tumaini trial will test the two new vaccine candidates, ChAdOx1 and mRNA-1469, following national approvals. The trial will also continue to test the Ervebo vaccine, which is being used to treat the Zaire species of the Ebola virus, to determine if it is effective against the Bundibugyo species. The ring-vaccination approach focuses on contacts of people with confirmed Ebola Bundibugyo.

The WHO and its partners pioneered the ring-vaccination strategy during the West Africa Ebola outbreak a decade ago. The strategy was successful in establishing the efficacy of the Ervebo vaccine in Guinea. Four vaccination rings have been set up, and several more are being prepared. Research into other potential treatments is also moving forward.

The introduction of the two new vaccine candidates is a significant development in the fight against the Ebola outbreak. According to health experts, this marks the first time that vaccines specifically designed for the Bundibugyo virus will be evaluated during an outbreak of the disease. The WHO's Technical Advisory Group on Candidate Vaccines Prioritization recommended the two vaccine candidates based on available evidence.

The clinical trial of the two new Ebola vaccine candidates is a collaborative effort between the WHO, the DR Congo government, and other partners. The trial aims to provide a new tool in the fight against the Ebola outbreak and ultimately bring it under control. The WHO and its partners remain committed to supporting the people of DR Congo in their efforts to combat the disease.

Key points

• The two new Ebola vaccine candidates, ChAdOx1 and mRNA-1469, will be tested in a clinical trial in the Democratic Republic of Congo.