Moderna has administered the first doses in a clinical trial for a vaccine targeting the Bundibugyo strain of Ebola, as the Democratic Republic of Congo (DRC) struggles to contain its most rapidly expanding outbreak of the disease on record. The Phase 1 trial, taking place in Canada, will enroll around 80 volunteers to assess the vaccine's safety, tolerability, and immune response.
The vaccine candidate uses Moderna's messenger RNA (mRNA) platform, the same technology that underpinned its COVID-19 shot. This approach allows for faster development and adaptation compared with traditional vaccine methods, a critical advantage in an outbreak where time is of the essence.
“Getting Moderna's vaccine candidate into a Phase 1 trial this rapidly is a major step forward in the fight against this deadly outbreak,” said Richard Hatchett, chief executive officer of the Coalition for Epidemic Preparedness Innovations (CEPI), a global public-private partnership that funds vaccine development against emerging infectious diseases.
CEPI announced in June that it would invest in a portfolio of vaccine candidates, including those from the International AIDS Vaccine Initiative, Moderna, and the University of Oxford. Oxford launched its own Phase 1 trial in July, with manufacturing planned at the Serum Institute of India. “Every day matters and every vaccine candidate in clinical trials gives us another shot at getting a safe, effective vaccine to the people who need it as swiftly as possible,” Hatchett added.
Outbreak spirals in eastern DRC
The DRC is now facing its second-largest Ebola outbreak in history, with cases growing faster than in any previous surge. As of Tuesday, the government reported 3,802 cases and 1,707 deaths. The epicentre is in Ituri province, which accounts for nearly 90% of cases, but the virus has also spread to five other provinces, including Kisangani, one of the country's largest cities.
Jean Kaseya, director-general of the Africa Centres for Disease Control and Prevention (Africa CDC), visited Bunia, near the outbreak's epicentre, and expressed deep concern about the trajectory. He noted that 60–70% of new cases are arising from community transmission rather than from known contact chains, a sign that contact tracing is failing to keep pace with the virus.
“Contact tracing is not working,” Kaseya said. “We don’t like the trajectory of this outbreak, and it’s already the second-largest outbreak (ever) in the world.”
The situation has prompted international health organisations to call for more aid, as the outbreak is spreading beyond the response capacity of local health systems. The World Health Organization has warned that without additional resources, the virus could continue to expand into new areas.
The development of a Bundibugyo-specific vaccine is particularly urgent because existing Ebola vaccines, such as the one used against the Zaire strain, do not protect against this variant. The Bundibugyo strain has a higher fatality rate and has caused sporadic outbreaks in Uganda and the DRC over the past decade.
Moderna's trial is part of a broader effort to create a universal Ebola vaccine that could cover multiple strains. The mRNA platform allows for rapid modification, which could prove crucial in future outbreaks. As the DRC battles this unprecedented surge, the race to develop an effective vaccine has never been more critical.
For more on the ongoing crisis, see our coverage of WHO's call for additional aid and the Oxford vaccine trial.
