BACKGROUND/OBJECTIVES: The 13-valent pneumococcal conjugate vaccine (PCV13) is part of routine immunization schedule in all provinces in Canada. Use of PCV13 has reduced incidence of important serotypes, and the impact of other PCVs on relevant serotypes is uncertain. The purpose of this study is to evaluate the health and economic implications of potential disease re-emergence following a switch to a lower-valent vaccine.
METHODS: A decision-analytic model was developed to estimate public health and economic impacts of a change in infant vaccination schedule over a 20 year time horizon. Historical pneumococcal disease surveillance data were used to estimate disease trends and to forecast serotype re-emergence and/or reduction. Serotype-specific incidence was modeled based on serotype coverage for infants (direct vaccination effects) and for older age groups (indirect effects of infant vaccination). The model compared maintaining PCV13 use versus switching to PCV10. For each vaccination program, health outcomes (cases of invasive pneumococcal disease, pneumonia, and acute otitis media) and associated health-care costs were estimated. Costs (2016 Canadian dollars), utility weights, and risk of disease-specific sequelae were derived from available published sources. Incremental cost-effectiveness ratios were calculated based on the costs and outcomes of each program. Costs and outcomes were discounted 3% per year. Univariate and probabilistic sensitivity analysis was undertaken to evaluate the impact of parameter uncertainty.
RESULTS: Continuing use of PCV13 resulted in fewer cases of pneumococcal disease in all age groups compared with switching to PCV10 due to the re-emergence of disease. While vaccine costs were higher for PCV13, medical costs due to disease were lower due to fewer cases of disease in the PCV13 population. The increase in disease and associated costs predicted continued use of PCV13 to remain cost-effective compared to starting a PCV10 program. Results were robust under multiple sensitivity analyses.
CONCLUSION: The results demonstrate continued use of PCV13 in Canada would provide a greater public health benefit compared to switching to PCV10. It is important that policy makers consider the potential implications of disease re-emergence when considering modifications to vaccination strategies.
