UK — The UK's Medicines and Healthcare Products Regulatory Agency (MHRA) approved clinical trials of a new Ebola vaccine developed by scientists at the University of Oxford. This is the first of four candidate vaccines targeting the Bundibugyo species of Ebola to enter human testing, with the initial doses expected to be administered to healthy adults in the UK within weeks.

The MHRA granted permission for the trials based on pre-clinical data from animal studies. Scientists at Oxford began developing the vaccine just eight weeks before receiving regulatory approval. Volunteers are now being recruited for a trial that will enroll 50 healthy adults aged 18 to 55, who will be monitored for one year following vaccination.

Dr. Katrina Pollock, chief investigator of the trial based at the University of Oxford, said: "We're doing phase one (early stage) trials of new vaccines all of the time, precisely to be ready for exactly this kind of outbreak." She added that severe side effects from similar vaccines are "very rare" and emphasized, "I want to stress that the Covid AstraZeneca vaccine was given to millions of people safely."

The vaccine uses the same viral vector technology as the Oxford/AstraZeneca Covid-19 vaccine, employing a genetically modified common cold virus that infects chimpanzees. It delivers a snippet of genetic code from the Bundibugyo species of Ebola, prompting the immune system to produce a single viral protein without causing infection. The candidate has already undergone testing in mice and macaque monkeys.

Vaccine researcher Alex Sampson said: "As soon as we heard there was an outbreak, we were able to scale up really, really quickly." He explained that the team accelerated development by running standard tests in parallel: "We're doing all the same tests that we would normally do, just we're able to do them in parallel, so it means a lot of teams working in lots of different places around the clock, but we're still doing everything that we would normally."

The Serum Institute of India is manufacturing the vaccine to clinical standards and has already stockpiled approximately 620,000 doses. Oxford researchers are also collaborating with partners in Uganda to prepare for future clinical trials in Africa.

The current Ebola outbreak, centered in the Democratic Republic of the Congo, has caused 1,792 laboratory-confirmed cases and 625 deaths. A public health emergency was declared on May 17. The outbreak is driven by the Bundibugyo species of Ebola, which has a fatality rate of about one-third and has caused two prior outbreaks. Of the six known Ebola virus species, no approved drugs or vaccines currently exist for the Bundibugyo strain.

Other organizations are also working on Bundibugyo-targeted vaccines. The International Aids Vaccine Initiative and U.S.-based Public Health Vaccines are developing their own candidates. The MHRA, an executive agency of the UK Department of Health and Social Care responsible for regulating medicines and medical devices, authorized the Oxford trial as part of a broader effort to respond rapidly to emerging viral threats.

Why It Matters

The urgency of this trial stems from the absence of approved countermeasures against the Bundibugyo Ebola species and the high fatality rate of the current outbreak. The University of Oxford’s ability to initiate human testing within two months of outbreak detection reflects a shift toward proactive vaccine development based on platform technologies proven during the pandemic—such as the adenovirus vector used in the Oxford/AstraZeneca Covid vaccine, which was credited with saving an estimated six million lives in its first year of use despite later restrictions in some countries due to rare blood clotting events affecting up to one in 100,000 recipients.