CEPI Commits $4.17M to Study Existing Ebola Vaccines Against Bundibugyo Strain

• Researchers are analyzing stored blood samples from thousands of individuals previously vaccinated with Ervebo and other Zaire-targeted regimens to test for cross-reactive antibody responses against the Bundibugyo strain.
• The projects are designed to provide rapid evidence to inform immediate public health responses, as no vaccine is currently licensed specifically for the Bundibugyo virus.
• Data gathered will help establish standardized serological assays and support the design of future Phase III clinical trials for broadly protective filovirus vaccines.

Addressing the Clinical Gap in Bundibugyo Outbreak Response

The current outbreak of the Bundibugyo ebolavirus in the DRC has prompted an urgent reassessment of existing medical countermeasures. While the World Health Organization (WHO) declared the situation a public health emergency of international concern, the absence of a licensed, pathogen-specific vaccine remains a significant hurdle. According to Dr. Richard Hatchett, Chief Executive Officer of CEPI, the reality of the current epidemiological landscape necessitates testing whether existing tools can be repurposed effectively.

“Given the recent announcement that Ervebo will be deployed for emergency use against Bundibugyo virus, these CEPI-backed studies will be all the more important to inform on how we can make the best use of the existing vaccine,” Dr. Hatchett stated. The strategy focuses on leveraging established cohorts to avoid the time-intensive process of building new trial infrastructure from scratch during a rapid-onset emergency.

Multi-Institutional Research Framework

The $4.17 million investment is distributed across four academic centers to maximize data diversity and ensure robust statistical analysis. Each group is tasked with evaluating the strength, durability, and cross-reactivity of antibodies generated by Zaire-targeted vaccines, such as Ervebo and the Zabdeno/Mvabea regimen, against the Bundibugyo virus.

The University of California, Los Angeles (UCLA) Fielding School of Public Health, led by Professor Anne Rimoin, is managing the largest portion of the cohort data, utilizing over 1,800 stored serum samples from 1,700 participants. This effort builds upon long-standing collaborations with the National Institute for Biomedical Research (INRB) in the DRC. Simultaneously, the Institute of Tropical Medicine (ITM) in Antwerp is executing the EBO-BOOST-BRIDGE project, which involves transferring critical laboratory methods to the INRB to ensure local diagnostic capacity is strengthened alongside the research.

The University of Oxford and the MRC-University of Glasgow Centre for Virus Research are focusing on complementary datasets. Oxford researchers are examining samples from Zaire ebolavirus survivors and vaccine recipients, while the Glasgow team is analyzing cohorts of healthcare workers and close contacts in Uganda and Scotland to determine if vaccine-induced antibodies recognize the Bundibugyo antigen.

Clinical Implications and Regulatory Path

The scientific community is operating under the guidance of the WHO’s Technical Advisory Group on Candidate Vaccine Prioritization, which has recommended prospective evaluation of Ervebo in a Phase III clinical trial. The primary objective of the CEPI-funded research is to determine if the immune response is sufficiently broad to offer protection, a phenomenon known as cross-reactivity.

The first antibody results from these studies are expected within two to six months, providing a critical window for evidence-based policymaking. Furthermore, the standardization of these serological assays will provide the foundational data necessary for future regulatory filings for both Bundibugyo-specific and pan-filovirus vaccine candidates.

Future Trajectory of Filovirus Research

By repurposing existing clinical trial samples, these institutions are effectively shortening the timeline for identifying viable therapeutic options.