Rabies kills an estimated 59,000 people each year, mainly in Africa and Asia, with children at greatest risk. Although effective vaccines exist, they typically require two or more clinic visits, making them difficult to deliver in many low-resource settings.
The new vaccine, ChAdOx2 RabG, is designed to be given in a single visit. In the trial, conducted in Tanzania, researchers tested its safety and the immune response it created. 63 adults and 111 children aged 2-6 years received either the new vaccine or a currently licensed rabies vaccine for comparison.
The researchers found that the new vaccine triggered much stronger immune responses than the currently available rabies vaccines. Antibody levels in adults were around five times higher than those seen with a single dose of the current rabies vaccines after a year, and in children they were more than eight times higher.
In children, the new, single-dose vaccine also outperformed a standard two-dose regimen of current vaccine recommended by the World Health Organisation. Nearly all children who received the new vaccine maintained antibody levels above the threshold considered protective against rabies one year after vaccination.
"Rabies is entirely preventable, yet it still causes tens of thousands of deaths each year, mostly among children," said Professor Sandy Douglas of the Jenner Institute, Nuffield Department of Medicine at the University of Oxford, the developer of the vaccine and the study’s senior author. "What makes this especially tragic is that existing vaccines work well, but they are difficult to deliver in the places where they are most needed.
"Our findings suggest that a single-dose vaccine could offer a practical and affordable way to protect vulnerable populations, particularly in rural and low-resource settings."
The study also found that the vaccine induced rapid immune responses, raising the possibility that it could be used not only for prevention before exposure, but potentially as part of emergency treatment after a bite. However, further research is needed to confirm this, with a follow-up study planned to start later in 2026.
Rabies is usually transmitted through dog bites, and global efforts to eliminate the disease focus on vaccinating dogs and improving access to post-exposure treatment. However, delivering multi-dose vaccination schedules remains a major challenge, particularly where access to healthcare is limited.
The researchers say that a low-cost, single-dose vaccine could make preventive vaccination programmes more feasible, especially in high-risk areas where current approaches are not widely used.
The trial is ongoing, with participants being followed for up to 5.5 years to assess how long protection lasts. Larger studies will also be needed to confirm the findings and support regulatory approval.
"If these results are confirmed in larger trials, this vaccine could be a game changer for rabies prevention," adds Dr Adam Ritchie, first author of the study and Senior Vaccinologist at the Jenner Institute. "In a world where wealthy travellers can be vaccinated but children living in the same high-risk regions rarely are, it has the potential to simplify vaccination, reduce costs, and ultimately save lives."
Dr Ally Olotu, Director of Science, Ifakara Health Institute, and local lead of the study concludes "Rabies is a preventable disease that still claims hundreds of lives across Tanzania and thousands across Africa and Asia annually.
"By demonstrating, with this vaccine that a simpler and more affordable vaccination schedule can provide strong protection, this trial brings us closer to making rabies pre-exposure prophylaxis accessible to the populations that need it most. The Ifakara Health Institute has been a major contributor in the country’s fight against Rabies and we are delighted to be a part of this exciting new development together with our partners."
The paper, ‘Safety and immunogenicity of a single-dose adenovirus-vectored rabies vaccine over 1 year in adults and children in Tanzania: interim data from an ongoing, partly randomised, controlled, phase 1b/2 trial’, is published in The Lancet Infectious Diseases.