Effectiveness of a publicly funded pneumococcal vaccination program against invasive pneumococcal disease among the elderly in Victoria, Australia

Within Australia, Victoria is the only jurisdiction where the 23-valent polysaccharide pneumococcal vaccine (23vPPV) has been publicly funded for the elderly (aged greater than or equal to65 years). We compared age-specific rates of invasive pneumococcal disease (IPD) for periods before and after implementation of the program, and data from a comparable Australian population that does not have a funded program. Vaccine effectiveness (VE) was estimated using the screening and indirect cohort methods. Compared to the pre-program period, there was a 36% reduction in the reported rates of IPD among persons aged greater than or equal to65 years. Adjusted for under-reporting in the referent rate, the decrease was equivalent to an annual reduction of 112 cases and an estimated 14 deaths among persons greater than or equal to65 years. VE was 71% (95% CI 54-82) using the screening method and 79% (95% CI -14 to 96) by the indirect cohort method. Both point estimates were consistent with the VE expected among persons aged greater than or equal to65 years, although the small number of isolates meant the indirect cohort method was inconclusive at the lower 95% confidence limit. Consideration should be given to publicly funding pneumococcal vaccine for this age group in other settings. (C) 2004 Elsevier Ltd. All rights reserved.