The global race to contain the escalating Ebola outbreak in the Democratic Republic of the Congo (DRC) has taken a new turn, with the Coalition for Epidemic Preparedness Innovations (CEPI) committing $4.17 million to four research projects aimed at determining whether existing Ebola vaccines can trigger protective immune responses against the Bundibugyo Ebola virus.
The studies, which will draw on blood samples stored from thousands of people who were previously vaccinated against Zaire ebolavirus, are expected to provide urgently needed scientific evidence as health authorities consider the use of existing vaccines against the related but distinct Bundibugyo virus.
The News Agency of Nigeria (NAN) reports that the development comes against the backdrop of an escalating outbreak in the DRC, which the World Health Organisation (WHO) declared a public health emergency of international concern in May.
CEPI said the research would focus significantly on people who received the Ervebo vaccine, which is licensed for protection against Zaire ebolavirus, as well as other vaccine candidates.
No licensed vaccine for Bundibugyo
CEPI Chief Executive Officer, Dr Richard Hatchett, said the urgency of the research was underscored by the absence of a licensed vaccine specifically targeting Bundibugyo virus.
He noted that although Bundibugyo-specific vaccine candidates were being developed, they would not be available during the earliest stages of the outbreak.
“However, vaccines do exist for the related Zaire ebola virus, including Ervebo.
“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,” he said.
The studies are expected to help researchers establish and standardise antibody tests for Bundibugyo virus while determining how long immune responses generated by existing vaccines persist.
The findings could also provide evidence needed to support future clinical trials and guide vaccination strategies if existing vaccines prove capable of offering some degree of protection against the virus.
WHO backs evaluation of Ervebo
According to CEPI, the WHO Technical Advisory Group on Candidate Vaccine Prioritisation has recommended that Ervebo should be evaluated in a Phase Three clinical trial alongside Bundibugyo-specific vaccine candidates once those candidates become available.
The recommendation reflects the urgent need to establish the effectiveness of vaccination options against Bundibugyo virus rather than relying solely on evidence from vaccines developed for the related Zaire ebolavirus.
The DRC authorities and the Africa Centres for Disease Control and Prevention have also announced plans to deploy Ervebo to priority groups under a protocol-governed expanded-use arrangement.
The emergency use of an existing vaccine, however, makes the new research particularly important because scientists need to determine whether the immune response generated by Ervebo can recognise Bundibugyo virus and potentially reduce the risk of severe disease.
UCLA gets largest research award
The University of California, Los Angeles (UCLA) Fielding School of Public Health will receive the largest of the four grants—$2.05 million—to investigate immune responses among recipients of Ervebo and Ad26.ZEBOV/MVA-BN-Filo vaccines.
The UCLA project will draw on data from more than 1,700 participants and approximately 1,800 stored serum samples, giving researchers access to a substantial body of biological material without having to wait for new participants to be recruited and vaccinated.
Professor of Epidemiology at UCLA, Prof. Anne Rimoin, said the institution’s long-standing partnership with the National Institute of Biomedical Research in the DRC would allow the research team to mobilise existing expertise and cohorts quickly.
“When an outbreak is moving this quickly, we cannot afford to start from zero,” she said.
The collaboration is expected to help accelerate the analysis and ensure that research findings can be generated while the public health response is still unfolding.
Antwerp project to assess cross-protection
The Institute of Tropical Medicine (ITM), Antwerp, will receive $1.02 million for its EBO-BOOST-BRIDGE project.
The project will analyse samples from more than 600 participants to determine whether existing vaccination can produce cross-protective immune responses against Bundibugyo virus and other related viruses.
Beyond generating scientific evidence, the project will also seek to strengthen laboratory capacity in the DRC by transferring testing methods to the National Institute of Biomedical Research.
CEPI said the first antibody results from the project are expected within two to six months, potentially providing important information during the ongoing outbreak response.
Oxford researchers to examine vaccine and natural immunity
The University of Oxford’s Nuffield Department of Medicine’s Centre for Human Genetics and Pandemic Sciences Institute will receive $975,000 for another study examining the potential protective effect of existing immunity.
Researchers will test blood samples from people who received the Ervebo vaccine as well as survivors of Zaire ebolavirus disease.
The objective is to establish whether antibodies generated either through vaccination or previous natural infection can recognise Bundibugyo virus and potentially offer protection against it.
Prof. Miles Carroll, Professor of Emerging Viruses at the University of Oxford and lead investigator of the study, said the results would be particularly important for public health authorities faced with decisions on whether and how rapidly to deploy existing vaccines.
The research could therefore help bridge a critical evidence gap between the availability of an existing Ebola vaccine and the lack of a vaccine specifically developed and licensed for Bundibugyo virus.
Glasgow study targets vaccinated contacts, health workers
The fourth project will be conducted by the MRC-University of Glasgow Centre for Virus Research, which will receive $120,000.
Researchers will examine samples collected from vaccinated close contacts and Ugandan healthcare workers to determine whether antibodies produced following Ervebo vaccination can also recognise Bundibugyo virus.
The relatively smaller study is expected to contribute additional evidence on the breadth of immune responses generated by Ervebo and help researchers understand whether vaccination could have value beyond its licensed target.
Research designed to accelerate outbreak response
CEPI said the four awards were selected through its June 2026 Call for Proposals, which sought to generate evidence to support Bundibugyo vaccine research and development.
The organisation said the projects were designed not only to answer immediate questions about the potential use of existing vaccines, but also to strengthen the scientific foundation for developing and evaluating vaccines specifically targeting Bundibugyo virus.
The research programme will also provide laboratories and researchers in affected and neighbouring countries with opportunities to strengthen their capacity to investigate emerging infectious diseases.
CEPI said the programme is supported by the European Commission through a 2026 Horizon Europe grant, the U.S. Department of State and CEPI’s existing core funding.
As the DRC continues to respond to the outbreak, researchers and health authorities are racing against time to determine whether an existing vaccine can provide a measure of protection while more targeted vaccines are developed and evaluated.
The outcome of the four studies could consequently influence decisions on emergency vaccination, clinical trials and future preparedness for outbreaks caused by Bundibugyo virus.