Climate change requires altering influenza vaccine distribution

New analysis suggests that warm winters tend to be followed by more severe influenza epidemics with earlier onsets.

The analysis, partially funded by the National Institutes of Health Fogarty International Center, was conducted on past influenza seasons in the United States beginning in 1997. The researchers found that similar pattern of harsher seasons following mild seasons holds true for both influenza A and B, according to

The authors said that when fewer people are infected with influenza during warm winters, they leave an unnaturally large portion of the population susceptible to infection the next season. This phenomenon, therefore, can lead to more severe epidemics that begin earlier than expected.

Continued global warming, the study postulates, will include warmer than normal winters that occur with more frequency. This leads the authors to suggest that the manufacture and distribution of influenza vaccines be ordered after mild winters in order to mitigate the severity of future epidemics.

"In the event of continued global warming, warmer than average winters are expected to occur more frequently, but variability in seasonal temperatures will of course remain, and average winters will still occur with regularity for some time to come," the authors write," reports. "Our work suggests that mild influenza seasons during unusually warm winters are a harbinger of the likelihood of an unusually severe season to come.

"Hence, these findings could guide improved prevention efforts, including progressive vaccination programs after a mild winter to achieve high vaccination coverage well in advance of the next influenza season."

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