Scientists keep vaccines stable without refrigeration
British scientists have found a way of keeping vaccines stable without refrigeration, which they say could transform vaccination campaigns in rural Africa.
British scientists have found a way of keeping vaccines stable without refrigeration, which they say could transform vaccination campaigns in rural Africa.
"Currently vaccines need to be stored in a fridge or freezer," said Dr Matt Cottingham of the Jenner Institute at the University of Oxford, who led the study. "You need a clinic with a nurse, a fridge and an electricity supply, and refrigeration lorries for distribution."
"If you could ship vaccines at normal temperatures, you would greatly reduce cost and hugely improve access to vaccines."
The team of researchers from Oxford University and Nova Bio-Pharma Technologies have mixed vaccines with the sugars sucrose and trehalose before slowly drying them on a filter or membrane.
As the water evaporates, the vaccine mixture turns into a syrup and solidifies on the membrane, preserving the active part of the vaccine and protecting it from degradation, even at high temperatures.
Flushing the membrane with water rehydrates the vaccine in a few seconds, the researchers explained in their study, which is published in the journal Science Translational Medicine.
Cottingham's team stored two different virus-based vaccines for up to six months at 45°C without any degradation.
They also found the vaccines could be kept for a year and more at 37°C.
"The beauty of this approach is that a simple plastic cartridge, containing the membrane with vaccine dried on, can be placed on the end of a syringe," said Dr Cottingham.
"Pushing a liquid solution from the syringe over the membrane would then release the vaccine and inject it into the patient.
The process could be used for many types of vaccines and sensitive biological agents.
"This is so exciting scientifically because these viruses are fragile. If we are able to stabilise these, other vaccines are likely to be easier," said principal investigator Professor Adrian Hill of the University of Oxford.
The next steps are to show that it can be scaled up to industrial manufacturing levels and also to demonstrate that it works with a standard or newly licensed human vaccine.
Under the World Health Organisation's (WHO) immunisation programme, nearly 80% of the children born are vaccinated against six killer diseases: polio, diphtheria, tuberculosis, whooping cough, measles and tetanus.
However, one of the biggest costs is maintaining the so-called "cold chain" - ensuring that vaccines are refrigerated from the manufacturer to the child, whether in a developed nation or a remote village in Africa.
The study was funded by the Bill and Melinda Gates Foundation and the Wellcome Trust.