New vaccine against rare Ebola strain could enter trials within months

Scientists at the University of Oxford are developing an experimental vaccine against a rare strain of the Ebola virus, which could be ready for clinical trials within the next two to three months. This was reported by the BBC.

The development comes amid growing concern over the outbreak in the Democratic Republic of the Congo, where 750 suspected cases and 177 deaths have been recorded to date. The current outbreak is caused by a rare species of the virus—the Bundibugyo strain—for which there is currently no approved and proven effective vaccine. The mortality rate for this strain reaches approximately one-third of those infected.

The World Health Organization has already raised the risk assessment in the Democratic Republic of the Congo from “high” to “very high.” Health authorities emphasize that the situation does not constitute a pandemic, but the declared public health emergency of international concern indicates the seriousness of the situation.

The new vaccine utilizes ChAdOx1 technology—the same platform developed by the Oxford team during the COVID-19 pandemic. The technology allows for rapid adaptation to various infectious diseases by incorporating specific genetic material from the pathogen. In the case of COVID-19, the platform used genetic information from the coronavirus. Now, scientists have modified it with genetic material from the Bundibugyo strain of Ebola. This approach uses a genetically modified chimpanzee adenovirus that has been made safe for humans. It acts as a “carrier” of genetic information to the cells, training the immune system to recognize and attack the virus.

“We are preparing for the worst-case scenario. We hope that contact tracing and quarantine measures will be sufficient, but we cannot afford to slow down,” stated Prof. Teresa Lambe, head of vaccine immunology at the Oxford Vaccine Group.

Animal testing is currently underway in Oxford to determine if the vaccine induces a sufficient immune response. The World Health Organization warns that animal data confirming the effectiveness of this specific candidate is still lacking, and development remains associated with many unknowns.

If results are positive, the Serum Institute of India is prepared to begin large-scale production of the vaccine. “Once we provide the necessary material, they can act quickly and on a large scale,” notes Prof. Lambe.

The Bundibugyo strain presents a particular challenge for scientists as it is extremely rare. Of the six known varieties of the Ebola virus, only three cause major outbreaks in humans. Bundibugyo has been identified only twice before—in Uganda in 2007 and in the Democratic Republic of the Congo in 2012. Since then, the virus had not been recorded for over a decade. While an approved vaccine already exists for the more common Zaire strain of the Ebola virus, such protection is still lacking for Bundibugyo.

Specialists emphasize that Ebola vaccines are not used for mass vaccination as they were for COVID-19. Instead, a “ring vaccination” strategy is applied—immunizing those at the highest risk of infection, including close contacts of the sick and medical personnel.

In parallel, Oxford scientists are also working on vaccines against other dangerous viruses, including the Sudan strain of Ebola and the Marburg virus.