UK scientists have successfully trialled vaccines that do not need to be kept cool in a fridge. These "fridge-free" versions could help address the issue of vaccine waste, as around half of all vaccines globally are discarded annually, mainly due to becoming unusable after exposure to unsuitable temperatures.
In a trial with 60 volunteers, company Stablepharma converted a liquid tetanus-diphtheria vaccine into a dry powder. This powder was stored at room temperature for a year before being mixed with water and injected. Professor Saul Faust, director of the NIHR Clinical Research Facility in Southampton, stated that the vaccine produced "equivalent" immune responses to the conventional version and was "safe and well tolerated" in these early studies.
The technology is inspired by resurrection plants, which use a sugar called trehalose to stabilise their cells during drought. The trial used trehalose to protect the vaccine's components. A larger trial involving 160 people is scheduled to begin in the coming months.
The World Health Organization (WHO) estimates that half of all vaccines globally are wasted. Failures in the "cold chain" – the strict temperature control needed during storage and transportation – are a major factor, particularly in remote areas or war zones where refrigeration and reliable electricity may be scarce.