June 24, 2014
By Reuters Staff
NEW YORK - More vaccines are lost to poor refrigeration than any other cause in the U.S., and the problem may be even worse in developing countries, where an intermittent power supply to the refrigerator or the lack of refrigerated transport can subject sensitive vaccines to higher temperatures.
Will climate change exacerbate the problem in the developing world, with rising ambient temperatures around medical centers? Dr. Biao Guo at Queensland University of Technology in Brisbane, Australia, and a research team that included the Chinese Center for Disease Control and Prevention in Beijing, China, examined the question using data from a pertussis vaccination program in Duanzhou in Guangdong province.
The province has a sub-tropical climate that might allow for study of the effect of higher ambient temperatures on diphtheria-tetanus-pertussis whole-cell (DTwP) and acellular (DTaP) vaccines.
Indeed, vaccines exposed to higher temperatures through handling outside of refrigeration and lower-than-recommended temperatures when refrigerated were associated with higher adverse reactions from the patients, the researchers found.
The researchers published their findings in a letter to the editor of Clinical Infectious Diseases.
Increases in the maximum temperature to which the vaccines were exposed coincided with relative risks for adverse events of 1.15 for DTwP and 1.07 for DTaP.
Minimum temperature increases were associated with a relative risk of 1.12 for DTwP and 1.05 for DTaP.
"It is important to maintain safety of DT(a/w)P and develop a more stable and effective pertussis-contained vaccine within the context of climate change," the researchers write.
Dr. Biao did not return requests for comment by press time.
Clin Infect Dis 2014.
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