A new single-shot rabies vaccine developed by researchers from the University of Oxford is showing promising results following a Phase 1 human clinical trial. Further clinical trials are now underway in the hopes the vaccine could help cut down the thousands of deaths every year from this viral disease.
Despite relatively effective vaccines having been available for several decades there are still around 60,000 deaths every year from rabies infections. The biggest challenge facing global public health agencies is that current rabies vaccines require two to three doses to be effective.
Alongside the difficulties in getting those extra doses to patients, rabies vaccines are notoriously expensive. Several doses of these vaccines can cost hundreds of dollars.
To solve this problem, a team of researchers at the University of Oxford has developed a novel vaccine that promises to be cheap and effective after just a single dose. The new vaccine leverages a platform developed by the Oxford team in 2020 in the quest for an effective COVID-19 vaccine.
The vaccine, dubbed ChAdOx2 RabG, uses a genetically weakened version of the common cold virus encoded to produce a rabies glycoprotein that helps train the immune system to detect future infections. The results of a preliminary Phase 1 human trial have just been published in The Lancet Microbe.
The trial recruited a dozen healthy volunteers to test three different doses of the novel vaccine. Within two months of vaccination all subjects in the medium- and high-dose groups developed levels of neutralizing antibodies against rabies that were above the threshold of efficacy required by the World Health Organization.
No adverse effects were reported beyond the standard short-term side effects generally seen with vaccinations. A long-term follow-up with most of the cohort revealed persistent neutralizing antibody levels one year after the single shot.
“We’re absolutely delighted with these early results – the vaccine has performed even better than we had expected,” reported chief investigator on the trial Sandy Douglas. “The problems with existing rabies vaccines are that they are expensive and require multiple doses. We’re very hopeful that expanded trials in countries affected by rabies will prove that this new vaccine could enable routine, affordable, single-dose vaccination against this devastating disease for people living in such areas.”
A Phase 2 trial in Tanzania is already underway testing the vaccine in a cohort of around 200 people. Preliminary results are expected from that trial later this year.
Daniel Jenkin, a clinical research fellow at the University of Oxford, said this novel vaccine could help save tens of thousands of lives.
“New rabies vaccines based on modern vaccine technologies could become important tools in preventing the tens of thousands of rabies deaths that occur annually,” said Jenkin. “Our strong early clinical trial data with ChAdOx2 RabG supports further development of this approach.”
The new study was published in The Lancet Microbe.
Source: University of Oxford
