Influenza Epidemics in the United States

ACCORDING to Selwyn D. Collins, head statistician of the United States Public Health Service (Public Health Rep., 59, 1483; 1944), in the eighteen major or minor epidemics of influenza that have occurred in the United States since the beginning of 1918, there has been great variability in the age curve. In the recent outbreak, the curve was in general similar to that of 1928–29 except for a very high incidence among children less than ten years of age. Pneumonic incidence in the current epidemic was far below that of 1918–19. Among persons less than twenty-five years of age the pneumonic rate was less in the current epidemic than in any of the others, but above twenty-five the rates corresponded closely to those recorded for the epidemic of 1928–29. The percentage of the total cases which were complicated by pneumonia in the 1943–44 epidemic was far below the figure for any other epidemic for which figures were available. In most of the epidemics the rates for influenza were consistently higher for females than for males, particularly adult females, with the exception of the 1918–19 epidemic and the minor outbreak of 1940–41, in which there were no obvious sex differences.