Influenza and pneumonia hospitalizations in Ontario: a time-series analysis

A comprehensive examination of gender and age-specific influenza and pneumonia hospitalization seasonality is currently lacking. Using population-based data for Ontario, Canada between April 1988 and March 2002 (n = 339803 hospitalizations), findings from this study revealed clear seasonality [Fisher's Kappa (FK) test = 68(.)64, P<0(.)001; Bartlett's Kolmogorov-Smirnov (BKS) test = 0(.)68, P<0(.)001] with consistent summer troughs and winter peaks for both sexes and all ages combined. The very young (both sexes 0-4 years) demonstrated the strongest seasonality (R-autoreg(2) = 0(.)97) and females aged 10-19 years, the weakest ( 2 R-autoreg(2) = 0(.)59). Gender differences were most pronounced in the oldest age groups (80 + years) where females had an average annualized peak rate of 250/100000 compared to 400/100000 for males. These findings can contribute to more population-specific prevention strategies and effective resource and service allocation based on seasonal and specific population demands.