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January 19, 1979

Rates of Pneumonia During Influenza Epidemics in Seattle, 1964 to 1975

Author Affiliations

From the Departments of Epidemiology (Dr Foy and Ms Allan) and Pathobiology (Drs Cooney and Kenny), School of Public Health and Community Medicine, University of Washington, Seattle.

JAMA. 1979;241(3):253-258. doi:10.1001/jama.1979.03290290021018

Influenza A epidemics were associated with a doubling to tripling of pneumonia rates among adult members of a prepaid medical care group studied between 1963 and 1975. Rates of influenza A associated with pneumonia increased with age. Influenza B epidemics did not have a similar effect. Overall pneumonia rates were highest in children younger than 5 years, but in this age group, other respiratory viruses dominated as causative agents. Influenza A and B epidemics were not always synchronized with those reported for the United States, and rates of influenza A infection varied between urban and suburban areas in sequential epidemics. In 1974, a year practically free from influenza A, a prolonged Mycoplasma pneumoniae epidemic kept rates of pneumonia high, especially during the summer.

(JAMA 241:253-258, 1979)