The world-first trial of a fridge-free tetanus-diphtheria vaccine has produced encouraging results that could improve access worldwide to crucial treatments.  

Around half of vaccines are wasted globally each year, according to the World Health Organization, because of temperature changes during storage and transport. 

Fridge-free vaccines have the potential to reduce dependence on refrigeration, improve access in more isolated communities and cut the environmental impact. 

The reformulated vaccine, known as SPVX02, was developed by UK-based biotech company Stablepharma using its StablevaX technology. 

The Phase I study found the vaccine was well tolerated, with no vaccine-related serious adverse events. The trial took place in the National Institute for Health and Care Research (NIHR) Clinical Research Facility at University Hospital Southampton. 

The research shows that SPVX02 can be stored at temperatures of up to 30°C for at least two years without losing its effectiveness. Scientists are now investigating whether it can remain stable for as long as four years. Researchers have also demonstrated that the vaccine remains stable, and fully potent, after three cycles of extreme temperature fluctuation from -20°C to +40°C. 

By 28 days after vaccination, all 60 participants receiving SPVX02 achieved protective antibody levels against both tetanus and diphtheria comparable to licensed vaccines. 

A Phase IIb trial will further assess the vaccine in a larger group of participants. 

Professor Saul Faust, Director of the NIHR Clinical Research Facility in Southampton and Professor of Paediatric Immunology and Infectious Diseases at the University of Southampton, said: “Keeping vaccines cold from the factory to the patient is one of the biggest challenges facing immunisation programmes worldwide. If larger studies confirm these findings, this technology could help transform the way vaccines are stored and delivered around the world.”