UK scientists are developing an experimental Ebola vaccine that could be ready for clinical trials within months, as health officials race to contain a deadly outbreak in the Democratic Republic of Congo.
Scientists at Oxford University are working on a vaccine targeting the Bundibugyo strain of Ebola, a rare form of the virus for which there is currently no proven vaccine or treatment.
The outbreak, centred in eastern DR Congo, has so far caused 750 suspected cases and 177 deaths, according to health officials. The World Health Organization has raised the national risk level in DR Congo from “high” to “very high,” while assessing the regional risk as high and the global risk as low.
The WHO declared the outbreak a public health emergency of international concern on Sunday, while stressing that it was not a pandemic.
Oxford researchers say their vaccine candidate could be ready for human trials in two to three months, although its effectiveness remains uncertain. Animal testing is now reportedly under way, and the WHO has said there is not yet animal data proving whether the candidate can protect against Bundibugyo Ebola.
The vaccine uses ChAdOx1 technology, the same platform used by Oxford scientists during the COVID-19 pandemic. The technology can be adapted quickly for different viruses by inserting genetic material from the targeted pathogen.
In this case, researchers have prepared the vaccine using genetic code from the Bundibugyo species of Ebola. The platform uses a modified chimpanzee cold virus that has been engineered to be safe for humans. It delivers genetic instructions to the body, training the immune system to recognise and fight the virus without causing Ebola infection or symptoms.
Professor Teresa Lambe, Calleva Head of Vaccine Immunology at the Oxford Vaccine Group, said speed was critical as scientists prepare for the possibility that the outbreak could worsen.
“People are worried about this outbreak,” Lambe told BBC News, adding that while contact tracing and quarantine may be enough, scientists could not afford to “take our foot off the gas.”
The Serum Institute of India is expected to mass produce the vaccine if Oxford can provide medical-grade starting material.
The current outbreak is especially difficult because Bundibugyo Ebola is rare. Ebola has six known virus species, but only three have caused major outbreaks in humans. Bundibugyo has previously caused outbreaks in Uganda in 2007 and DR Congo in 2012, but had not been detected for more than a decade.
A vaccine exists for the more common Zaire strain of Ebola, but not for Bundibugyo.
Health officials say any Ebola vaccine would likely be used through “ring vaccination,” targeting people most at risk, including close contacts of confirmed cases and healthcare workers treating infected patients.
Oxford researchers had already been working on vaccines for other dangerous viruses, including Sudan Ebola and Marburg, before the latest outbreak raised fresh concerns.