Researchers develop technology to preserve vaccines in tropical temperatures

Feb 19 2010

A team of British researchers have developed a simple, low-cost method to preserve vaccines in tropical climates, which they say could help to revolutionalize vaccination campaigns in developing countries, Reuters reports. The technology, tested by Oxford University scientists and developed by Nova Laboratories, "would remove the need for costly infrastructure, like fridges and freezers that require power and can break down, and highly trained staff," the news service writes, adding that the research was funded by the Bill & Melinda Gates Foundation and the Wellcome Trust (Kelland, 2/17).

In the "proof-of-concept" study, published Wednesday in the journal Science Translational Medicine, the researchers describe the steps taken to preserve "two malaria vaccines that are currently in human clinical trials," CBC News reports. "The technique involves mixing the vaccine's live viruses with two sugars, sucrose and trehalose. The solution is then dried out on a plastic film and hardens into glass. Inside the sugar-glass, the vaccine is immobilized and kept in suspended animation. To prepare the vaccine for injection, the glass is flushed with water and quickly dissolves, reactivating the vaccine," CBC News explains (2/17).

According to the study, the researchers were able to store the two virus-based vaccines on the "sugar-stabilized membranes for 4 to 6 months at 45 degrees Celsius (113F) without the medicines being damaged," Reuters continues. "They also found the vaccines could be kept for a year or more at 37 degrees Celsius with only tiny losses of vaccine," according to the news service (2/17).

USA Today's "Science Fair" blog writes, "Today vaccines for all the major childhood killers - flu, diphtheria, tetanus, whooping cough, polio, mumps, measles and chicken pox - require refrigeration (Weise, 2/17). According to Reuters, "one of the biggest costs of [WHO's childhood vaccine programs] 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 (2/17). Cold chain aherence "costs up to $US200 million a year," and the WHO estimates that adds as much as 20 percent to the cost of the vaccine, ABC News reports (Griffiths, 2/17).

Lead author Matt Cottingham, of the University of Oxford, said in a statement, "If you could ship vaccines at normal temperatures, you would greatly reduce cost and hugely improve access to vaccines. You could even picture someone with a backpack taking vaccine doses on a bike into remote villages," CBC News reports. "The researchers said further testing is needed to see if the sugar-glass can withstand temperature extremes and physical conditions typically seen in overseas shipping," writes CBC News (2/17).