Moderna is developing a vaccine candidate against the Bundibugyo ebolavirus (BDBV) for the ongoing outbreak in eastern Democratic Republic of Congo, deploying its mRNA platform in a race to contain a virus for which no licensed vaccine or therapy currently exists. The outbreak, declared a Public Health Emergency of International Concern by the World Health Organization on 17 May 2026, has already produced 906 suspected cases and 223 deaths as of 29 May, with cases also confirmed in Uganda. By 27 May, the DRC alone had recorded 1,077 suspected cases, 246 confirmed infections and 246 suspected deaths, concentrated in the conflict-affected provinces of Ituri, North Kivu and South Kivu.
Moderna and CEPI: a $50m push for a BDBV vaccine
Moderna has entered a partnership with the Coalition for Epidemic Preparedness Innovations (CEPI) to accelerate development of an investigational BDBV vaccine. CEPI, a global partnership created to drive forward vaccines against epidemic and pandemic threats, has committed up to $50m to the project. The funding will support preclinical development and early clinical testing – a Phase 1 trial – of Moderna’s candidate, which uses the same mRNA technology that underpinned the company’s Covid‑19 vaccines. A key element of the agreement is support for parallel manufacturing: producing doses while clinical evaluation is under way, so that if initial safety and immunogenicity data are favourable, the programme can move swiftly into larger Phase 2/3 trials.
The collaboration builds on Moderna’s existing research into filoviruses and expands its long‑standing strategic partnership with CEPI, which focuses on accelerating vaccine development for diseases with pandemic potential. Moderna had previously announced early‑stage research into a hantavirus vaccine in collaboration with the US Army Medical Research Institute of Infectious Diseases and Korea University College of Medicine – work that predated a recent cruise‑ship outbreak and that has, the company has noted, been misconstrued online as evidence that hantavirus is a hoax.
CEPI’s role in funding vaccine development for epidemic threats is central to the global response. The organisation is not only backing Moderna but has also committed funding to two other BDBV candidates. The University of Oxford, with manufacturing by the Serum Institute of India, is receiving up to $8.6m for a candidate based on the ChAdOx1 platform – the same technology used in the Oxford‑AstraZeneca Covid‑19 vaccine. This candidate could be ready for testing within two to three months, pending additional animal data. The International AIDS Vaccine Initiative (IAVI) is receiving up to $3.2m for a candidate built on the rVSV platform, identical to the technology behind the approved Zaire‑strain Ebola vaccine. IAVI’s rVSV Bundibugyo candidate is considered promising but may take an estimated seven to nine months to be ready for clinical trials. CEPI’s funding strategy ties each award to a commitment to equitable access, aiming to ensure that any successful vaccines are made available to those who need them.
Additional funding and the wider response
Separately, the global vaccine alliance Gavi has pledged up to $50m to support the outbreak response. Up to $40m of that sum is earmarked to accelerate vaccine access, enabling manufacturers to commit to high‑capacity production even while development outcomes remain uncertain. A further $10m is dedicated to outbreak response needs and to protecting routine immunisation services in affected areas. Gavi currently funds the global Ebola vaccine stockpile, which contains Ervebo – a vaccine licensed only for the Zaire ebolavirus species, not for Bundibugyo. Any decision to deploy Ervebo against BDBV would require further assessment and WHO guidance.
The Pandemic Fund has announced up to $220.6m in grants to address critical response gaps, including the reprogramming of existing resources and expedited financing for affected and at‑risk countries. The Gates Foundation has committed an initial $15m in emergency funding, distributed among the Africa CDC ($5m for regional coordination, rapid deployment and cross‑border surveillance), WHO AFRO ($5m for frontline operational support) and WHO Headquarters ($5m for rapid procurement of diagnostics and surge logistics).
WHO recommendations on treatments and vaccine use
The WHO last week recommended prioritising several experimental drugs for evaluation in clinical trials. Because there are no approved therapies for Bundibugyo virus disease, the organisation has identified monoclonal antibodies – MBP134 from Mapp Biopharmaceutical and Maftivimab from Regeneron – as priority candidates. Regeneron has stated that a supply of Maftivimab is already on the ground in the DRC. The antiviral remdesivir, from Gilead Sciences, which was approved in 2020 for Covid‑19, has also been prioritised. The WHO is additionally recommending the evaluation of a combination therapy using a monoclonal antibody together with remdesivir. For post‑exposure prophylaxis, Gilead’s experimental oral antiviral obeldesivir has been flagged as a priority, though its utility depends on effective contact tracing, which remains operationally challenging in the insecure provinces where transmission is concentrated.
On the vaccine front, the WHO has advised that Merck’s Ervebo – the only licensed Ebola vaccine – should not be deployed outside carefully designed research settings for the Bundibugyo strain, as evidence of its cross‑protective efficacy against this species is limited and inconclusive. The Bundibugyo virus, first identified in Uganda in 2007, has historically produced lower case fatality rates (roughly 25‑50%) than other Ebola strains, but severe disease and death remain significant risks. The development of vaccines and therapeutics for less common Ebola strains such as BDBV has been hampered by a historical lack of commercial interest, a dynamic also observed in the context of hantavirus research. The WHO’s recommendation that all candidate treatments and vaccines be tested exclusively within clinical trials is designed to generate robust data on their safety and efficacy, even as response efforts continue to be complicated by insecurity, difficulties in contact tracing and inadequate healthcare infrastructure across Ituri, North Kivu and South Kivu.