“Animal studies for the Oxford vaccine candidate are already under way and will be progressing with partners around the world. As for timelines, Serum Institute of India is an organisation that goes far and fast. So we are hoping to have clinical grade vaccine doses ready within two to three months,” Prof Teresa Lambe, Head of Vaccine Immunology, Oxford Vaccine Group, Pandemic Sciences Institute, University of Oxford, told a virtual meeting today. Co-designer of the Oxford AZ vaccine against Covid, Prof Lambe said that researchers are aiming for a single-dose vaccine, similar to the licensed Ebola Zaire vaccine.
The vaccine effort builds on more than a decade of work with the ChAdOx platform, the same technology behind the Oxford COVID-19 vaccine. Scientists say this existing knowledge has allowed them to move unusually quickly. Oxford’s manufacturing partners, including the Oxford Biomanufacturing Facility, Coalition for Epidemic Preparedness Innovations (CEPI) and the Serum Institute of India, are helping accelerate production and clinical preparation.
Oxford is also working with global partners to accelerate the generation of supportive pre-clinical data for the development and testing of the ChADOx-based monovalent Bundibugyo Ebolavirus candidate vaccine ChAdOx1 BDBV in outbreak scenarios.
The Ebola outbreak in the Democratic Republic of Congo and Uganda has been a fast-moving one according to the World Health Organisation (WHO) Director-General Dr Tedros Adhanom Ghebreyesus. He recently said it was outpacing response efforts with the number of suspected deaths rising to 220.
The current bout of Ebola, which causes haemorrhagic fever and high mortality, has been caused by the Bundibugyo strain of the virus. Currently, no vaccine or specific treatment has been approved to prevent or treat Ebola disease caused by the Bundibugyo virus strain.
Will a one-shot vaccine be effective?
Experts said that efforts were also under way towards prevention trials for healthcare workers and high-risk contacts of infected individuals. One strategy being explored is “ring vaccination,” where people surrounding a confirmed case are vaccinated or given preventive treatment. “The aim is to produce a single-dose vaccine, similar to the licensed Ebola Zaire vaccine. Scientists believe both antibodies and T-cells (immune cells that identify and fight pathogens),will be important for protection, although there is still limited understanding of long-term immunity against the Bundibugyo strain,” Prof Lambe told The Indian Express.
“Pre-clinical models for these pathogens have already shown that a single-dose vaccine can protect animals. So, we are optimistic that a one-shot vaccine is achievable. Given the current outbreak, which appears to be relatively large at the moment, we are hopeful that the WHO and its partners will be able to contain it. A single-dose vaccine is our goal and many others in the field share that objective,” he said.
As for the immunological challenges involved in achieving long-lasting protection, he said details on the Bundibugyo virus were still scarce. “We still lack a detailed mechanistic understanding of what drives immunity against other filoviruses. What we do know is that both antibodies and T cells play important roles in protection. Our aim is, therefore, to develop a vaccine that can strengthen both antibody and T-cell responses against Bundibugyo. We hope the vaccine will be available within the next two to three months,” Prof Lambe said.
However Oxford scientists cautioned that the vaccine remains investigational and still needs rigorous testing for safety and effectiveness.
What about treatment?
Researchers have launched the PARTNERS trial, a multi-country adaptive randomized controlled trial for Ebola therapeutics. Designed during previous outbreaks and modelled on COVID-era clinical trials, the platform is designed to rapidly test and evaluate therapeutics such as monoclonal antibodies ( MBP134) and antivirals (such as remdesivir) during sudden disease outbreaks in regions like the DRC and Uganda.
These were first tested during the 2024 Marburg outbreak in Rwanda and are now being adapted for the current Ebola emergency. Two drugs are currently included in the trial. According to Dr Amanda Rojek, Associate Professor of Health Emergencies, Pandemic Sciences Institute, University of Oxford, the priority however is to ensure that they are safe for human use. “Before these treatments can be used, they must undergo rigorous testing. The length of the trial will depend on how well the therapy performs during testing,” Dr Rojek said.
She also acknowledged that regulatory approvals were being fast-tracked in Uganda and the DRC. Teams on the ground are assessing whether treatment centres can safely support clinical studies in difficult security conditions.
Scientists are evaluating post-exposure prophylaxis using beldesivir, an oral prodrug (this is an inactive or poorly active medication that is converted into its active, therapeutic form through natural metabolic processes after it is swallowed or administered) of remdesivir, which could help prevent disease in recently exposed contacts. Dr Richard Hatchett, CEO of CEPI, said that one of the things that really characterised this outbreak is the speed with which partners have come together. “Cases have now been identified across a vast region stretching from South Kivu to northern Atori and eastward as far as Kampala. The affected zone forms a rough triangle covering approximately 80,000 square kilometers and is home to an estimated 15 million people. This is a large, densely populated area,” Dr Hatchett said.
He also observed that while speed was essential as scientists were working on vaccines and therapeutics, scientific rigour cannot be compromised. “Even during an emergency, vaccines and treatments must still be proven safe and effective before they can be widely used outside clinical trials,” he said.
Is reduced aid funding affecting research?
Meanwhile, Sir Andrew Pollard, Ashall Professor of Infection and Immunity, Pandemic Sciences Institute and Director of the Oxford Vaccine Group, cautioned against cuts to global health and research funding. “There is little doubt that reductions in aid funding weaken the capacity to detect outbreaks early. While I can’t speak to the specific evidence in this particular case, fewer personnel on the ground are now connected to international aid networks, which clearly increases risk. For now, much of the funding that was approved in Europe before these reductions is still supporting ongoing work. However, cuts in US funding have already led to some research programmes being suspended, though not to my knowledge, any current Oxford-led activities,” he said.
Scientists also pointed out that even if the outbreak is controlled before vaccines are widely deployed, the work being done now will still shorten response times for future outbreaks.
The World Health Organisation on May 17 sounded the alarm bells, declaring the ebola outbreak a public health emergency of international concern. (File Photo) 
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