A tetanus and diphtheria vaccine that requires no refrigeration has completed its first phase of human trials, with results suggesting it remains effective after being stored at room temperature for up to two years, scientists have announced.
The vaccine, known as SPVX02, was developed by UK pharmaceutical company Stablepharma Ltd, with specialist laboratory testing provided by the UK Health Security Agency. Evaluation of the Phase 1 trial results, carried out at UKHSA’s Vaccine Development and Evaluation Centre, indicated the vaccine retained its effectiveness after long-term storage at 30°C for 24 months — without the need for a cold chain.
The development is considered a significant step in addressing one of the most persistent challenges in global immunisation. Most vaccines must be kept at a constant cold temperature from the point of manufacture through to the point of administration, a requirement known as the cold chain. When that chain is broken, vaccines can lose their potency and may need to be discarded entirely. The World Health Organization estimates that up to half of all vaccines worldwide fail to reach their intended recipients, citing cold chain difficulties as a major contributing factor.
The problem is particularly acute in remote regions, during humanitarian emergencies, and in countries with unreliable electricity infrastructure — precisely the contexts where vaccine access is most critical. A thermostable vaccine capable of withstanding higher temperatures without losing effectiveness could dramatically reduce wastage and simplify distribution in those settings.
SPVX02 will now advance to the next stage of clinical trials, which will involve a larger group of healthy participants and a direct comparison with a vaccine already licensed for use in Europe. The trial is expected to take place at clinical study sites across the UK over the coming months, with UKHSA continuing to assess immune responses among participants.
Dr Bassam Hallis OBE, Deputy Director of UKHSA’s Vaccine Development and Evaluation Centre, said the progress represented “an excellent example of the huge contribution that the UK continues to make to transform public health through innovative technological and scientific advances.”
Dr Karen O’Hanlon, Chief Operating Officer at Stablepharma and lead of the SPVX02 programme, said vaccines free from refrigeration requirements “offer a clear path to a more equitable, resilient, and sustainable healthcare system,” describing the development as “not just a scientific innovation, but a public health and climate solution.”
Professor Saul Faust, Director of the NIHR Southampton Clinical Research Facility, said the collaboration had “accelerated the translation of this technology from laboratory science to potential patient impact” and reinforced the UK’s leading role in global vaccine research and development.
The programme has been supported by Innovate UK and the National Institute for Health and Care Research Southampton Clinical Research Facility, and represents a collaboration between the UK biotech sector, government bodies, and academia.
