Public health authorities are currently scrambling to secure medical countermeasures for an outbreak of the Bundibugyo strain of the Ebola virus in the Democratic Republic of Congo. With 2,473 confirmed cases and 999 deaths reported by the government, the lack of approved vaccines or treatments for this specific strain—which carries a fatality rate of up to 40%—has prompted an urgent international search for viable clinical options.
Experimental Vaccine Pipelines and Clinical Trials
The University of Oxford initiated the first human trial for a Bundibugyo-specific vaccine in July. According to the sources, the vaccine utilizes ChAdOx1 technology—the same platform used for the Oxford/AstraZeneca COVID-19 vaccine. The Serum Institute of India has already manufactured and stockpiled approximately 620,000 doses to prepare for potential emergency needs, with 4,000 doses supplied for the initial trial involving 50 healthy adults.
The World Health Organization (WHO) has identified the rVSVΔG/BDBV-GP vaccine, developed by the International AIDS Vaccine Initiative, as the most promising candidate. This vaccine, which employs technology similar to Merck’s approved Ervebo shot for the Zaire strain, demonstrated survival benefits in 2023 non-human primate studies. Development of this candidate is expected to take seven to nine months before it is ready for assessment in a clinical trial, according to the WHO.
Did you know?
The Bundibugyo ebolavirus (BDBV) is distinct from the more common Zaire strain. Because most existing Ebola protocols were designed for the Zaire virus, health officials are examining whether any existing Ebola treatments might offer protection.
Antibody-Based Therapies and Antiviral Drugs
Clinical trials are underway in Congo to test Mapp Biopharmaceutical’s MBP134, a monoclonal antibody combination. The WHO has recommended prioritizing this drug for clinical trials among confirmed BDBV cases. Additionally, the U.S. Biomedical Advanced Research and Development Authority (BARDA) has shipped doses for compassionate use in the region.
Regeneron Pharmaceuticals is also evaluating its candidate, maftivimab, which has been shown in a lab to be active against the Bundibugyo strain. While the company’s related product, Inmazeb, is FDA-approved for the Zaire strain, Regeneron has donated 500 doses to the WHO, providing a potential resource if found helpful.
For post-exposure treatment, Gilead Sciences’ experimental oral antiviral, obeldesivir, is being considered by the WHO. Preclinical data suggest the drug could provide protection, as it showed up to 100% protection in monkeys against other Ebola strains. Laboratory studies conducted by the University of Texas Medical Branch also indicate that Gilead’s remdesivir may have stronger activity against BDBV than against the Zaire Ebola strain.
Advancements in Diagnostic Testing Capacity
The WHO indicated that limited testing capacity for the Bundibugyo strain was slowing response to the outbreak. To address this, several firms have introduced or updated testing kits. Shanghai ZJ Bio-Tech’s Ebola Virus (EBOV) Real Time RT-PCR Kit received an Emergency Use Listing from the WHO on July 2, making it the first diagnostic test for the Bundibugyo species to be added to the WHO’s Emergency Use Listing.
Other diagnostic tools currently in use or under review include:
- Roche/TIB MOLBIOL: A research-use-only molecular PCR test developed to detect Ebola Bundibugyo virus.
- BioFire Defense: The BioFire Global Fever Special Pathogens Panel, which is FDA-cleared to detect multiple Ebola species.
- Altona Diagnostics: The RealStar Filovirus Screen RT-PCR Kit 1.0, currently being used to detect the outbreak in Congo.
- OraSure Technologies: The OraQuick Ebola 2.0 Rapid Antigen Test, which recently received FDA Emergency Use Authorization.
Pro Tip:
When monitoring outbreaks, check the WHO’s Emergency Use Listing (EUL) regularly. This list provides verified information on which diagnostics and treatments are authorized for immediate deployment in crisis zones.
Frequently Asked Questions
Are there any approved vaccines for the Bundibugyo Ebola strain?
No. Currently, there are no approved vaccines or treatments for Bundibugyo. All candidates are in experimental stages or clinical trials.
How does the Bundibugyo strain compare to the Zaire strain?
The Zaire strain is more common and has approved vaccines like Ervebo. Bundibugyo (BDBV) requires different diagnostic and therapeutic approaches, as existing treatments for Zaire may not be fully effective.
What is the fatality rate of this outbreak?
The Bundibugyo ebolavirus has a fatality rate of up to 40%, according to government data from the Democratic Republic of Congo.
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