NOVA SCOTIA, CANADA / RankWire.AI / – Moderna has begun testing a new vaccine targeting Bundibugyo ebolavirus in an early-phase clinical trial as the Democratic Republic of the Congo faces an escalating outbreak. The first volunteer received the initial dose of the mRNA-1469 vaccine on August 3 in Truro, Nova Scotia, marking the vaccine’s debut in human subjects. The World Health Organization has declared the Congolese outbreak an international public health emergency.
The Phase 1 trial will include approximately 80 healthy adults across three sites in Canada. Its primary goals are to assess the vaccine’s safety, tolerability, and its capacity to generate an immune response. This trial does not aim to demonstrate the vaccine’s effectiveness in preventing Ebola infection. Typically, early-stage studies focus on safety and dosage before advancing to larger-scale tests. The Coalition for Epidemic Preparedness Innovations has pledged up to $50 million to fund testing, manufacturing, and additional research doses.
WHO reported 3,605 confirmed cases and 1,587 deaths in DR Congo as of July 30. By that date, at least 651 patients had recovered. Updated figures on August 4 indicated cases had surpassed 3,800 with over 1,700 deaths. Authorities identified infections in 49 health zones across five provinces, with Ituri remaining the outbreak’s epicenter, accounting for roughly 88% of confirmed cases.
Outbreak underscores absence of approved vaccine
The ongoing epidemic involves Bundibugyo ebolavirus, a member of several species within the Ebola virus family. Currently, there is no approved vaccine or targeted treatment for this particular species. Existing licensed Ebola vaccines are designed against Zaire ebolavirus, which causes a different form of the disease. Historically, Bundibugyo ebolavirus has triggered outbreaks in Uganda and DR Congo, with the country experiencing 17 Ebola outbreaks since the virus was first identified in 1976.
Transmission occurs through direct contact with infected blood, body fluids, organs, or contaminated objects. Efforts by public health teams include expanding testing, contact tracing, treatment, and infection control measures across affected regions. By July 30, authorities had listed 17,863 contacts for monitoring. WHO has also documented 151 confirmed infections among healthcare workers, including 44 fatalities. The outbreak response faces challenges from armed conflicts, population movements, and attacks on health facilities, which hinder access to some communities.
Additional vaccine candidates progress in development
Following Moderna’s efforts, the University of Oxford in Britain launched another Phase 1 trial, with the first dose administered on July 24. The Oxford candidate is based on the ChAdOx1 platform, whereas Moderna’s vaccine employs messenger RNA technology. The Serum Institute of India produced the Oxford vaccine and assembled a stockpile of about 620,000 doses, along with 4,000 investigational doses for research purposes.
Both programs are supported by CEPI as part of a broader initiative to develop vaccines against Bundibugyo Ebola. The organization also funds two other candidates utilizing recombinant vesicular stomatitis virus technology. One was developed by IAVI with manufacturing led by Hilleman Laboratories, while Public Health Vaccines developed the other. Currently, none of these candidates have received approval for widespread public use. WHO emphasizes that ongoing surveillance, laboratory diagnosis, patient care, safe burials, and community engagement are critical components of the outbreak response efforts.