As population ages, flu takes deadly turn

The annual toll of influenza has risen dramatically since the late 1970s, according to an analysis of U.S. death statistics. One major factor is the advancing average age of the population. Another is the increasing prevalence of virulent strains of the flu virus.

Influenza is typically not a direct cause of death, but researchers at the Centers for Disease Control and Prevention in Atlanta, estimated the disease’s contribution to mortality by noting seasonal fluctuations in deaths that might have resulted from underlying flu infections. Bacterial pneumonia, for example, can be a fatal consequence of severe flu.

Such calculations suggest that influenza claimed more than 68,000 lives on average during each of the last three flu seasons of the 1990s, William W. Thompson and his colleagues report in the Jan. 8 Journal of the American Medical Association (JAMA). That’s well up from about 16,000 annual deaths attributable to flu during a similar period 2 decades earlier.

People over age 65 are nearly 100 times as likely to die from flu than people 5 to 50 years old are, and the efficacy of flu vaccinations wanes in older adults.

Responding to the new findings in the same issue of JAMA, David M. Morens of the National Institutes of Health in Bethesda, Md., urges physicians to get annual flu shots, in order to avoid transmitting the virus to patients. They should also encourage their patients, especially older ones, to get the shots, he says. “Even an imperfect vaccine, used optimally, can prevent many thousands of deaths,” says Morens.


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