The University of Oxford’s Oxford Vaccine Group successfully vaccinated its first volunteer in the world’s first clinical trial of a vaccine designed to protect against the Bundibugyo ebolavirus. According to the University of Oxford, the volunteer received the first dose of the candidate vaccine, known as ChAdOx1 BDBV.
Oxford Launches First Human Trial for Bundibugyo Ebola Vaccine
Professor Teresa Lambe led the Ebola vaccine team at the University of Oxford. She stated that the vaccine was created rapidly due to decades of prior research. Researchers emphasized that the trial vaccine cannot give anyone Ebola. Prof Lambe explained that the aim of the phase one clinical study is to evaluate safety and determine whether the vaccine generates a strong immune response capable of protecting against the Bundibugyo species.
The trial is supported by funding from the Coalition for Epidemic Preparedness Innovations (CEPI) as part of an $8.6 million program awarded to the University of Oxford and the Serum Institute of India (SII) to advance Bundibugyo vaccine development activities. Dr. David Pulido-Gomez, Global Chemistry, Manufacturing and Controls lead at the Pandemic Sciences Institute within the Nuffield Department of Medicine, noted that the candidate vaccine was taken from concept to clinic in eight weeks. The vaccine utilizes the same technology as the AstraZeneca Covid-19 vaccine.
Outbreak Severity and Vaccine Development Background
The clinical trial launches during a severe outbreak in the Democratic Republic of the Congo. CIDRAP noted that the Bundibugyo virus is fueling the fastest-growing Ebola outbreak on record, with cases centered in the northeastern part of the country.
While a licensed vaccine exists against the Zaire species of Ebola, it does not work directly against Bundibugyo. There are four vaccines currently in development against the Bundibugyo species, but Oxford’s candidate is the first to enter human trials.
Following the initial trial in Oxford, the team plans a second small Ebola vaccine trial in Uganda, subject to regulatory approval, followed by a larger efficacy study in DR Congo. The Serum Institute of India has already manufactured hundreds of thousands of doses ready for deployment if trials succeed, with sources citing 600,000 to 620,000 manufactured and 4,000 experimental doses provided for the initial test.
Evaluating Existing Zaire Vaccines for Cross-Protection
As researchers pursue strain-specific vaccines, public health agencies are simultaneously debating whether existing licensed vaccines can offer partial cross-protection. A study published in the New England Journal of Medicine analyzed blood samples from adults and children vaccinated with existing Zaire-targeted vaccines to measure antibody responses against Bundibugyo.
The research evaluated Merck’s Ervebo vaccine and a two-dose regimen produced by a Johnson & Johnson subsidiary consisting of Zabdeno and Mvabea. The findings showed that three months after a single dose of Merck’s Ervebo, the antibody response was about eight times lower for Bundibugyo compared to Zaire, while the two-dose Johnson & Johnson regimen produced six times more antibodies for Zaire than for Bundibugyo.
These results sparked discussions among global health organizations regarding potential prime-boost strategies or emergency deployment. Africa CDC, in partnership with Médecins Sans Frontières (MSF) and other partners, has worked on designing a phase-2 clinical trial to test existing vaccine regimens among frontline health workers. At least 121 health workers and other frontline responders have been infected during the outbreak, with 36 deaths reported among them.
However, the World Health Organization and Merck have expressed caution. The WHO Strategic Advisory Group of Experts on Immunization planned to examine the cross-protection data further during meetings.
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