Impact of pneumococcal vaccination on pneumonia hospitalizations and related costs in Ontario: a population-based ecological study

Background — In Ontario, Canada, pneumococcal conjugate vaccine (PCV) was approved for infants in 2001 and became part of the publicly funded routine immunization schedule in 2005. We assessed the population-level impact of PCV on pneumonia hospitalizations and related costs.

Methods — We used the difference-in-differences (DD) approach to evaluate the impact of pneumococcal vaccination on pneumonia hospitalizations and related costs, using non-pneumonia hospitalization as the control condition. We extracted monthly hospitalization costs, stratified by age group, from population-based health administrative data between April 1992 and March 2014. The study period was divided into five intervals: pre-vaccine period, availability of seven-valent PCV (PCV7) for private purchase, public funding for PCV7, replacement of PCV7 with 10-valent PCV (PCV10), and replacement of PCV10 with 13-valent PCV (PCV13).

Results — A total of 1,063,700 pneumonia hospitalizations were recorded during the study period. In the vaccine-eligible age group, pneumonia hospitalizations declined by 34% (95% CI, 32%–37%), 38% (95% CI, 32%–43%), and 45% (95% CI, 40%–51%) and hospitalization-related costs declined by 38% (95% CI, 25%–51%), 39% (95% CI, 33%–45%), and 46% (95% CI, 41%–52%) after public funding for PCV7, PCV10, and PCV13, respectively. Pneumonia hospitalizations and related costs also declined substantially for PCV-ineligible older children and elderly (>65 years) age groups.

Conclusions — Our results suggest that the publicly funded PCV immunization program is responsible for substantial reductions in pneumonia hospitalizations and related healthcare costs, among both young children eligible for publicly funded vaccination and other age groups not included in the publicly funded program.