Abstract

Baseline levels of mortality in the United States in the absence of influenza epidemics were estimated using cyclical regression models applied to national vital statistics from October 1972 to May 1985. Models were developed by age and by region. Results from 1983 to 1985 are preliminary. More mortality than predicted by the theoretical baseline occurred during nine influenza seasons. Epidemics with high morbidity in children and young adults occurred in 1976/77 and 1978/79. Regional differences in the impact of influenza occurred occasionally. Total influenza-associated excess mortality in six epidemics from the winters of 1972/73 to 1980/81 was about 200,000. About 80-90 per cent of excess mortality occurred in persons over 64 years old.