The world-first trial of a fridge-free tetanus-diphtheria vaccine has produced encouraging results that could improve access worldwide to crucial treatments, while reducing carbon emissions.
Around half of vaccines are wasted globally each year, according to the World Health Organization. Millions of doses are lost because of temperature changes during storage and transport.
Fridge-free vaccines have the potential to transform vaccine delivery by reducing this dependence on refrigeration. This would improve access in more isolated communities and cut the environmental impact by reducing vast amounts of energy that lead to emissions.
This phase I study, led by the University of Southampton and University Hospital Southampton NHS Foundation Trust, found the vaccine was well tolerated, with no vaccine-related serious adverse events.
Results are published in The Lancet group's eClinicalMedicine .
Professor of Paediatric Immunology and Infectious Diseases at the University of Southampton and Director of the NIHR Clinical Research Facility in Southampton, who led the study, said: "Keeping vaccines cold from the factory to the patient is one of the biggest challenges facing immunisation programmes worldwide. Our study suggests that this vaccine can remain safe and effective without refrigeration.
"If larger studies confirm these findings, this technology could help transform the way vaccines are stored and delivered around the world."
The trial
The trial took place in the National Institute for Health and Care Research (NIHR) Clinical Research Facility at University Hospital Southampton and was delivered through the NIHR Biomedical Research Centre: Southampton .
The reformulated vaccine, known as SPVX02, was developed by UK-based biotech company Stablepharma using its StablevaX technology.
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.
The randomised trial, which also involved the Medicines Evaluation Unit (MEU) in Manchester, enrolled 60 healthy adults.
By 28 days after vaccination, all participants receiving SPVX02 achieved protective antibody levels against both tetanus and diphtheria, demonstrating immune responses comparable to licensed vaccines.
Next steps
The eClinicalMedicine publication follows the launch of a Phase 2b trial that will further assess the vaccine in a larger group of participants.
Stablepharma's technology platform, StablevaX, can be applied to vaccines, small molecules, peptides and biologics. They are currently working with a partner to thermostabilise small molecule oncology and anti-infective products, in addition to other vaccines.
Özgür Tuncer, Stablepharma CEO and Executive Director, said: "This peer reviewed validation represents a pivotal moment for our StablevaX platform and the future of thermostable vaccines. These findings strengthen the scientific and global health case for a new generation of fridge free vaccines, particularly in regions where cold chain limitations hinder equitable access."
Health and Social Care Minister Diana Johnson said: "This pioneering research demonstrates how British innovation is helping to tackle some of the biggest challenges in global healthcare, and providing life-saving breakthroughs for use around the world.
"Right now, people are dying of preventable diseases all over the world, not due to a lack of vaccines, but a lack of refrigeration. Fridge-free vaccines have the potential to be a game-changer for global health, especially for people in remote communities, or regions affected by conflict.
"Backed by NIHR's world-leading research, this breakthrough shows once again how our investment in science and life sciences is driving better health outcomes, while supporting economic growth and reinforcing the UK's position at the forefront of medical innovation."
Stablepharma's SPVX02 vaccine has been developed with support from Innovate UK, part of UK Research and Innovation (UKRI). It is a reformulated version of the WHO-prequalified Tetadif tetanus-diphtheria vaccine. Scientists from the UK Health Security Agency (UKHSA) provided specialist laboratory testing.
Stablepharma expects to complete the clinical development programme for SPVX02 by 2027.
