The Coalition for Epidemic Preparedness Innovations (CEPI) has announced the urgent fast-tracking of three investigational vaccine candidates aimed at combating the Bundibugyo ebolavirus (BDBV) epidemic currently afflicting communities in the Democratic Republic of Congo (DRC) and Uganda. This critical intervention, following a comprehensive global review and extensive consultations with leading health organizations including the World Health Organization (WHO) and Africa Centres for Disease Control and Prevention (Africa CDC), underscores the escalating threat posed by BDBV and the absence of licensed prophylactic measures. The selected candidates, developed by IAVI, Moderna, and the University of Oxford, represent a multi-pronged scientific approach to an elusive and deadly pathogen.
The Urgent Imperative: Addressing the Bundibugyo Threat
The current BDBV outbreak in the DRC and Uganda has cast a stark light on a significant gap in global health security. Unlike the more commonly encountered Zaire ebolavirus, for which a licensed vaccine (Ervebo) exists, there are presently no approved vaccines specifically targeting Bundibugyo ebolavirus, nor are any in advanced clinical development. This lack of preparedness is particularly alarming given the high fatality rates associated with Ebola viruses and their potential for rapid, uncontrolled spread in vulnerable populations. The BDBV strain, while historically less frequent in its outbreaks compared to Zaire ebolavirus, is nonetheless highly virulent, causing severe hemorrhagic fever that can quickly overwhelm healthcare systems.
Richard Hatchett, CEO of CEPI, emphasized the gravity of the situation in a recent press release, stating, "With Bundibugyo virus spreading rapidly and no licensed vaccines, every day counts in the race against this deadly disease. CEPI’s urgent funding and support for these three promising candidates aims to advance safe, effective vaccines to help control this epidemic." This statement highlights not only the immediate threat but also CEPI’s proactive mandate to accelerate the development of vaccines against emerging infectious diseases with epidemic or pandemic potential. The organization’s strategy involves investing in promising candidates across diverse technological platforms to increase the likelihood of success and ensure a robust pipeline for future threats.
The Bundibugyo ebolavirus, first identified in 2007 during an outbreak in the Bundibugyo district of Uganda, has caused only two previous documented outbreaks before the current events. Its sporadic nature has historically meant less investment in targeted vaccine development compared to the more prevalent Zaire strain. However, the current epidemic in a region already grappling with complex humanitarian challenges and fragile health infrastructures necessitates an immediate and coordinated global response. The affected areas in the DRC and Uganda are often remote, making disease surveillance, containment, and medical intervention particularly challenging, further amplifying the urgency of vaccine deployment.
CEPI’s Strategic Investment and Collaborative Framework
CEPI, established in 2017 following the devastating West African Ebola epidemic, operates as a global partnership between public, private, philanthropic, and civil society organizations. Its core mission is to accelerate the development of vaccines against known epidemic and pandemic threats and to enable access to these vaccines for affected populations during outbreaks. The decision to fast-track these three BDBV vaccine candidates is a direct embodiment of this mission, leveraging CEPI’s expertise in epidemic preparedness and its capacity to mobilize significant financial and scientific resources.
The selection process for these candidates was rigorous, involving a global review of available scientific data and expert consultations. This multi-stakeholder approach, involving critical input from the WHO, which provides global health leadership and technical guidance, and the Africa CDC, which plays a pivotal role in strengthening disease surveillance and response capabilities across the African continent, ensures that the chosen candidates align with global health priorities and regional needs. This collaborative framework is essential for navigating the complex scientific, ethical, and logistical challenges inherent in developing and deploying vaccines during an active outbreak.
The Frontrunners: A Trio of Promising Technologies
The three vaccine candidates represent different, yet proven, technological approaches, maximizing the chances of developing an effective and safe vaccine against BDBV.
1. IAVI’s rVSV Vaccine: Leveraging a Proven Platform
IAVI’s candidate, originally developed at The University of Texas Medical Branch (UTMB), is based on a recombinant vesicular stomatitis virus (rVSV) platform. This technology utilizes a modified, harmless virus (VSV) to deliver genetic material from the Ebola virus, prompting the human immune system to produce protective antibodies. A significant advantage of the rVSV platform is its ability to elicit robust protective immunity after a single dose, which is crucial in outbreak settings where rapid protection is paramount and multi-dose regimens may be difficult to administer.
This rVSV technology is not new to the fight against Ebola. It forms the basis of the only licensed vaccine for Zaire ebolavirus, Ervebo (manufactured by Merck), which has been successfully deployed during multiple outbreaks, including the significant 2018-2020 Zaire Ebola outbreak in the DRC. Furthermore, the same technology was utilized during a 2025 Sudan virus outbreak in Uganda, demonstrating its versatility and rapid deployability against different filoviruses.
While the IAVI candidate has demonstrated protective efficacy in non-human primate studies, a critical step in preclinical evaluation, it has not yet been evaluated in humans. The WHO has identified this candidate as the most promising among those selected by CEPI, largely due to its proven platform and the established pathway for its development and regulatory approval. CEPI’s funding, totaling $3.2 million, will be instrumental in supporting the critical early-stage manufacturing steps. This includes the generation of a Master Virus Seed stock and the transfer of processes to a contract development and manufacturing organization (CDMO) for Good Manufacturing Practice (GMP) production. These steps are foundational for initiating human clinical trials and ensuring the vaccine can be produced at scale if proven effective.
2. Moderna’s mRNA Platform: Building on COVID-19 Success
Moderna’s candidate utilizes the cutting-edge messenger RNA (mRNA) platform, a technology that gained global prominence and validation during the COVID-19 pandemic. mRNA vaccines work by delivering a synthetic mRNA sequence that instructs human cells to produce a harmless piece of the virus’s spike protein, triggering an immune response. The key advantages of mRNA technology include its speed of development, flexibility for rapid adaptation to new variants or pathogens, and the potential for scalable manufacturing.
CEPI is making a substantial investment of up to $50 million in Moderna’s BDBV candidate. This significant funding is earmarked for preclinical testing, Phase 1 clinical trials, and, critically, simultaneous manufacturing. This accelerated approach is designed to allow the program to advance immediately into Phase 2 and 3 trials if the Phase 1 results are successful, dramatically shortening the typical vaccine development timeline. Stephane Bancel, CEO of Moderna, reiterated the company’s commitment, stating in the press release, "We will move with urgency and scientific rigor to support the response and help bring a potential vaccine closer to the communities that need it most."
Financial and Strategic Implications for Moderna: The CEPI investment holds particular significance for Moderna. The company’s financial performance in recent quarters has shown a decline from its peak during the COVID-19 pandemic. Its revenue in the fourth quarter of last year was down 30% year over year, and the first quarter of 2026 brought in only $0.4 billion, with approximately 80% coming from international markets. In 2025, Moderna reported spending $3.1 billion on research and development expenses, while bringing in only $1.9 billion in revenue, indicating a substantial investment in its pipeline.
In this context, CEPI’s investment effectively offloads a significant portion of the financial risk associated with developing a vaccine for a rare disease like Bundibugyo ebolavirus, where the outbreak is localized and the commercial market is limited. This grant allows Moderna to continue proving the versatility and efficacy of its mRNA technology against a new pathogen and accumulate valuable clinical data for its broader filovirus pipeline, all at little financial cost to the company. It represents a strategic opportunity for Moderna to demonstrate the enduring value of its platform beyond COVID-19 and to contribute to global health preparedness, aligning with its long-term vision for mRNA technology.
A Contrasting Policy Landscape: Interestingly, CEPI’s substantial investment in Moderna’s mRNA technology comes at a time when the U.S. government under the Trump administration has taken steps to curtail its own mRNA research programs. In August 2025, the Trump administration reportedly terminated 22 contracts focused on developing mRNA vaccines and wound down additional federal investments in mRNA technology. This divergence highlights a potential disparity in strategic priorities, with CEPI and its global partners championing the continued advancement of mRNA technology for broad epidemic preparedness, even as some national governments scale back domestic programs. This contrast underscores the critical role of international organizations like CEPI in maintaining momentum in key scientific areas vital for global health security.
3. University of Oxford’s ChAdOx1 Vector: A Versatile Workhorse
The University of Oxford’s vaccine candidate is based on the ChAdOx1 viral vector platform, a technology that gained widespread recognition as the backbone of AstraZeneca’s highly successful COVID-19 vaccine. This platform uses a weakened and non-replicating common cold virus (adenovirus) found in chimpanzees to deliver genetic material from the target pathogen. The ChAdOx1 platform is known for its robust immune response and a well-established manufacturing process.
Beyond COVID-19, the ChAdOx1 technology has demonstrated efficacy against a range of related filoviruses, including Zaire ebolavirus, Sudan virus, and Marburg virus, underscoring its potential as a broad-spectrum tool for hemorrhagic fever viruses. CEPI has invested $8.6 million in Oxford’s candidate, funding preclinical testing, the creation of a Master Virus Seed stock, and the production of clinical-grade doses. This investment will enable Oxford to rapidly advance its candidate through the initial stages of development, building on its extensive experience with viral vector vaccines.
The Broader Landscape of Ebola Preparedness and Future Outlook
The coordinated effort by CEPI to fast-track these three diverse vaccine candidates is a testament to the ongoing global commitment to strengthening epidemic preparedness. While the immediate focus is on the Bundibugyo ebolavirus, the broader implications extend to the development of platform technologies that can be rapidly adapted to other emerging threats. The existence of multiple Ebola virus species (e.g., Zaire, Sudan, Bundibugyo, Taï Forest, Reston) means that a comprehensive approach to Ebola preparedness requires a robust pipeline of vaccines, potentially including multi-strain or pan-Ebola candidates.
As work on these three candidates commences, CEPI remains committed to evaluating additional promising candidates, including through an ongoing open call for proposals. This continuous assessment ensures that the most effective and innovative solutions are brought to the forefront. Beyond development, CEPI is also actively coordinating with key global health partners, including Gavi, the Vaccine Alliance, the World Bank, and various development finance institutions, to ensure that surge financing is available for large-scale procurement and equitable distribution if any of these trials prove successful. This foresight addresses the critical challenge of ensuring that life-saving vaccines, once developed, can reach the communities that need them most, regardless of their economic circumstances.
The development of vaccines for rare and localized outbreaks presents unique challenges, including the ethical complexities of conducting clinical trials in affected populations during an emergency, and the logistical hurdles of manufacturing and distributing vaccines to often remote and underserved regions. However, the collaborative model spearheaded by CEPI, involving international organizations, academic institutions, and pharmaceutical companies, demonstrates a pathway forward for overcoming these obstacles. This initiative not only addresses an immediate public health crisis but also reinforces the global architecture for responding to future epidemics, ensuring that the world is better prepared for the next unforeseen pathogen. The urgent fast-tracking of these Bundibugyo ebolavirus vaccine candidates is a critical step towards realizing a world where epidemics are no longer a threat to humanity.
