Variations in age distribution of poliomyelitis. Comparative ratios of younger and older age groups

Abstract

Summary 1. The seasonal fluctuation in cases of poliomyelitis in New York City for those under 10 years of age and those over 10 years was examined from 1944 to 1952, inclusive. 2. Annual variations were observed in the seasonal occurrence of cases. The two age groups examined tended to conform to the pattern of incidence that prevailed in any given year. 3. The trend in the percentage distributionof cases by age and week of onset revealed differences between the two age groups considered. In the younger age group it decreased to a low point in the thirty-fifth week and then increased. In the older age group the reverse trend was noted. 4. The use of a decrease in reported cases of poliomyelitis in young age groups following administration of gamma globulin as a gauge of its effectiveness should be made with caution.