Scientists at England’s Oxford University have found a way of keeping vaccines stable without refrigeration, BBC News reported Feb. 19.
Writing in Science Translational Medicine, they say the breakthrough could significantly help efforts to immunize more children in rural Africa.
The need to keep vaccines cool — to stop them deteriorating — is often difficult in developing countries where refrigerators, clinics and electricity cannot be taken for granted.
Writing in the journal Science Translational Medicine, the scientists describe how they managed to keep vaccines stable for four to six months at 113 degrees Fahrenheit.
They also found the vaccines could be kept for a year or more at 98.6 degrees Fahrenheit with only tiny losses of vaccine.
Their work was published Feb. 17.
The researchers mixed two different virus-based vaccines with two types of sugar before slowly drying them on a filter paper. They used sucrose and trehalose, which is known for its preservative properties.
This preserved the vaccine doses, which were then easily rehydrated when needed for injection.
Under the World Health Organization's immunization program, nearly 80 percent of children are vaccinated against six killer diseases — polio, diphtheria, tuberculosis, whooping cough, measles and tetanus.
But one of the biggest costs of that program is maintaining the so-called "cold chain" — ensuring vaccines are refrigerated all the way from the manufacturer to the child, whether in a developed nation or a remote village in Africa.
The WHO estimates that maintaining the cold chain costs up to $200 million a year in developed countries, increasing the cost of vaccination by as much as 20 percent.
"Currently vaccines need to be stored in a fridge or freezer," said Matt Cottingham of Oxford's Jenner Institute, who led the study. "You need a clinic with a nurse, a fridge and an electricity supply, and refrigeration lorries [vehicles] for distribution."
Several teams of scientists around the world are working on ways to try to overcome the problem.
"If you could ship vaccines at normal temperatures, you would greatly reduce cost and hugely improve access to vaccines. Without the need for refrigeration, you could even picture someone with a backpack taking vaccine doses on a bike into remote villages."
The work, funded by the Bill and Melinda Gates Foundation and the Wellcome Trust, involved a collaboration between the university scientists and Nova Bio-Pharma Technologies.
In a commentary about the study, Professor Adrian Hill, said: "If we could convert all the standard vaccines to a solution like this, it would mean they're cheaper to deliver, because they'd survive at room temperature — and so there'd be scope to vaccinate more children.
"The technology is simple and extremely cheap — and there are no more scientific hurdles to overcome.
"Our tests were pretty tough as we used live viruses. So we feel that having stabilized those more fragile vaccines, this method should work for other vaccines containing dead protein.
"It's now just a matter of developing the technique, trying it out in Africa and seeing if it can be made on an industrial basis. This could happen within five years."