WHO Launches Clinical Trial to Evaluate Ebola Vaccines in the Democratic Republic of Congo

The World Health Organization (WHO) announced on Tuesday the launch of a clinical trial in the Democratic Republic of the Congo to evaluate vaccines against the “Bundibugyo” strain of the Ebola virus, with the aim of determining their effectiveness in preventing infection and limiting transmission.

Dr. Meg Doherty, the WHO’s technical lead for vaccine trials, said during a press conference in Geneva—where she participated via video link from Bunia, the capital of Ituri Province in the DRC—that the trial, initiated a few days ago under the leadership of the Congolese government, is being managed by the National Institute of Biomedical Research in collaboration with local and international researchers.

She explained that the trial allows for the evaluation of one or several vaccines within a unified research framework, using a “ring vaccination” approach that targets contacts of confirmed cases to measure the vaccines’ ability to prevent infection and curb the spread of the virus.

Doherty noted that Ervebo is the first vaccine to be evaluated due to its availability in the country, adding that its efficacy against the “Zaire” strain of Ebola has been proven, while its ability to prevent the “Bundibugyo” strain remains unknown.

She pointed out that WHO technical advisory groups are reviewing scientific evidence on two vaccines under development against Bundibugyo: ChAdOx1, developed by the University of Oxford in collaboration with the Serum Institute of India, and the Moderna vaccine. Recommendations on these vaccines will be issued once the data review is complete.

Doherty emphasized the importance of distinguishing between a vaccine’s effectiveness in preventing infection and its ability to reduce disease severity and mortality. She clarified that the current trial focuses on preventing new infections and viral transmission, while other studies examine the impact of Ervebo on disease severity and death rates.

She confirmed that obtaining reliable scientific results will take several months, and the expected data will help health authorities identify appropriate vaccines to address the outbreak.

Doherty considered the launch of the trial a significant step toward providing the scientific evidence needed to support health decisions and enhance population protection against the disease during the current outbreak and future ones.