Aggregate influenza vaccine effectiveness against hospitalization and all-cause mortality estimated by GEE with adjustment, propensity score matching, and stratification: 2000–01 to 2005–06.

Note. IVE = influenza vaccine effectiveness; CI = confidence interval.aAll covariates include: age, sex, socio-economic status, urban residency, prior influenza immunization (two year), prior pneumococcal immunization, medical visits prior year, and Elixhauser index;bSelect covariates include: age, prior influenza immunization (two year), pneumococcal immunization, medical visits prior year;cMatched on propensity scores derived based on all covariates: age, sex, socio-economic status, urban residency, prior influenza immunization (two year), prior pneumococcal immunization, medical visits prior year, and Elixhauser index;dSelect adjustment includes: age, prior pneumococcal immunization, medical visits prior year;ePneumonia, influenza, or acute respiratory disease listed as most responsible admission diagnosis;fPre-influenza period estimates for hospitalization do not include 2003–04;g2003–04 year excluded from all estimates related to all-cause mortality since the pre-influenza period constitutes the main comparison period for that outcome and was missing for 2003–04 owing to early influenza period.