Perdrizet J, Horn EK, Hayford K, Grant L, Barry R, Huang L, McDade C, Wilson M. Estimating the historical population-level impact of PCV13 national immunization programs on invasive pneumococcal disease in Australia, Canada, Israel, England & Wales, and the United States. Poster presented at the ISPPD-12 (International Society of Pneumonia and Pneumococcal Diseases); June 19, 2022. Toronto, Canada.

BACKGROUND: Since pediatric national immunization programs (NIPs) switched from the 7-valent (PCV7) to the 13-valent pneumococcal conjugate vaccine (PCV13), invasive pneumococcal disease (IPD) attributable to the additional six serotypes in PCV13 has declined. The objective of this study was to investigate the annual population-level impact of PCV13 NIPs on IPD incidence due to PCV13-unique serotypes (1, 3, 5, 6A, 7F, 19A) among children and adults.

METHODS: We reviewed surveillance data from countries that introduced PCV7 followed by PCV13 in their NIP and reported annual serotype- and age-specific IPD incidence (Australia, Canada, Israel, England & Wales, and the United States). For each age group (<2, 2-<5, and ≥65 years), we calculated the annual relative change in IPD incidence and incidence rate ratio (IRR) compared to the year prior to PCV13 program initiation.

RESULTS: Decreases in PCV13-unique serotype IPD incidence in each age group were generally consistent in the five countries following the introduction of PCV13 in the pediatric NIP (Figure 1). Over an 80% average reduction in IPD caused by PCV13-unique serotypes (IRR=0.2) among <2 and 2-<5 year olds and approximately a 60% average reduction among ≥65 year olds (IRR=0.4) was observed after four years of pediatric PCV13 use (Figure 2). PCV13-unique serotype IPD incidence decreased more rapidly among children than adults in the first years of PCV13 use. From year 5 onwards, IPD incidence plateaued among all age groups.

CONCLUSIONS: Surveillance data from these five countries suggest that pediatric PCV13 use provides a high degree of direct and indirect protection against PCV13-unique serotypes.

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