Oxford Bundibugyo Ebola Vaccine Candidate Enters Clinical Trials in Uganda

Global health authorities have deployed 70,000 doses of the Ervebo vaccine to frontline workers in the Democratic Republic of the Congo, relying on the global stockpile to blunt a massive hemorrhagic fever epidemic. However, virological evidence contradicts this stopgap strategy. Ervebo is engineered specifically for the Zaire ebolavirus, leaving it unproven against the Bundibugyo species actually driving the current surge.[5][6]

To close this critical vulnerability, a targeted Phase I clinical trial for a Bundibugyo-specific vaccine candidate launched in Masaka City, Uganda, on October 6, 2026. The candidate, ChAdOx1 BDBV, was developed by the University of Oxford to directly neutralize the exact viral strain currently spreading across central Africa.[1][2][5]

The urgency stems from the unprecedented scale of the ongoing crisis in the Democratic Republic of the Congo. Since the outbreak was declared in May 2026, the DRC health ministry has recorded 8,728 confirmed cases and 4,205 deaths, yielding a case fatality rate of 48.2 percent.[5][6]

"The Bundibugyo ebolavirus outbreak raging in the DRC is now the fastest-growing Ebola epidemic in history, and the deadliest Ebola outbreak the nation has ever experienced," said Dr. Nicole Lurie, executive director of emergency preparedness and response at the Coalition for Epidemic Preparedness Innovations, which is funding the trial.[1][2]

The virus has already demonstrated its capacity to cross international borders. Earlier in October, Kenya confirmed its first imported case of Bundibugyo Ebola after a patient traveling from the DRC died in Nairobi, elevating the regional threat level and accelerating the push for a viable immunization.[4][5]

Engineering a targeted viral vector

The Oxford candidate relies on a well-established viral vector mechanism rather than live Ebola virus. ChAdOx1 BDBV uses a weakened, genetically modified chimpanzee adenovirus that cannot replicate in humans. Scientists engineered this carrier virus to deliver the genetic instructions for the Bundibugyo ebolavirus surface glycoprotein.[1][2]

Once injected, the vector enters human cells, which read the genetic code and temporarily produce the Ebola glycoprotein. The immune system recognizes this foreign protein and builds targeted antibodies and T-cells against it, creating a defensive memory without ever exposing the patient to the actual hemorrhagic pathogen.[1][2]

This is the exact technological platform that underpinned the Oxford/AstraZeneca COVID-19 vaccine. By reusing a vector with an extensive safety profile, researchers bypassed years of foundational testing, allowing them to rapidly swap the genetic payload and move the Bundibugyo candidate into human trials.[1][4]

Running simultaneous trials across different demographics allows researchers to establish a broader safety baseline. The Uganda trial follows the launch of a parallel first-in-human Phase I study in the United Kingdom, which is also evaluating the ChAdOx1 BDBV candidate.[1][2][4]

Scaling production for emergency deployment

Vaccine development frequently stalls at the manufacturing phase, but this trial bypassed the bottleneck through a massive parallel production run. The Serum Institute of India collaborated with Oxford to manufacture and stockpile approximately 620,000 doses of the ChAdOx1 BDBV candidate in just two weeks.[1][2][3]

While the Serum Institute supplied roughly 3,000 investigational doses for the initial Phase I trial in Uganda, the remaining hundreds of thousands of vials sit ready for immediate deployment. If early safety data proves favorable, this stockpile could support emergency use authorization in the DRC.[1][3]

Dr. Umesh Shaligram, executive director at the Serum Institute of India, emphasized the logistical achievement. "The rapid manufacture, stockpiling and supply of investigational doses for clinical evaluation reflect what can be achieved when global collaborators work with urgency and shared purpose," Shaligram stated.[1][2][3]

Professor Simon Drysdale, chief investigator of the study at the Oxford Vaccine Group, noted the collaborative scale of the effort. "A vaccine developed and first tested at the University of Oxford, and manufactured and stockpiled in India, is now being evaluated in Uganda with our expert partners," Drysdale said.[1][2][4]

Clinical evaluation in Masaka City

The clinical evaluation is being implemented by the Medical Research Council, Uganda Virus Research Institute, and the London School of Hygiene and Tropical Medicine Uganda Research Unit. The first healthy adult volunteers received their injections at the unit's Masaka City facility.[1][2]

Uganda offers an ideal testing ground due to its extensive experience managing viral hemorrhagic fevers and its robust clinical infrastructure. The Bundibugyo virus itself was first identified during a 2007 outbreak in western Uganda, giving local researchers a deep historical mandate to defeat the pathogen.[1][2]

Professor Eugene Ruzagira, the principal investigator for the Uganda study, highlighted the operational stakes. "By evaluating the ChAdOx-based Bundibugyo Ebola vaccine candidate in Uganda, we are generating the evidence needed to determine whether it is safe and capable of stimulating the immune responses that could help protect at-risk communities," Ruzagira said.[1][2]

The trial will meticulously track the volunteers to measure both the safety profile of the injection and the magnitude of the antibody response it provokes. This data will dictate whether the vaccine can safely advance to larger, late-stage efficacy trials in active outbreak zones.[1][2]

A broadening pipeline of candidates

The Oxford vector is not the only technology racing to fill the Bundibugyo immunity gap. Wessam Mankoula, the Ebola response lead for the Africa Centers for Disease Control and Prevention, confirmed that a second candidate is also advancing toward regional testing.[5][6]

An mRNA-based Bundibugyo vaccine candidate developed by Moderna recently received ethical approval to begin Phase Ib trials in Uganda. That candidate initiated its Phase Ia safety trials in Canada in August 2026, marking a dual-platform approach to securing a viable defense.[5][6]

Simultaneously, the Coalition for Epidemic Preparedness Innovations has partnered with the African biopharmaceutical company Minapharm Group, injecting $16.5 million to develop yet another Bundibugyo vaccine candidate, ensuring that multiple biological mechanisms are tested against the virus.[5]

For the frontline workers currently relying on the mismatched Ervebo vaccine in the DRC, these trials represent the only definitive exit strategy. Over 7,700 healthcare workers have received the Zaire-specific injection under compassionate use protocols, but supply shortages recently forced a suspension of further dosing.[5][6]

The trajectory of the DRC epidemic now depends on how quickly these experimental doses can clear regulatory hurdles. Until a Bundibugyo-specific vaccine proves its efficacy and reaches the field, regional health ministries remain entirely dependent on traditional contact tracing and isolation to slow the pathogen's advance.[5][6]