BACKGROUND: While pneumococcal conjugate vaccines (PCVs) have considerably reduced invasive pneumococcal disease (IPD) burden of vaccine serotypes, a rise in IPD attributable to non-vaccine serotypes (NVT) has been observed. This study estimates the annual population-level trends in NVT IPD incidence after PCV13 introduction in pediatric national immunization programs (NIPs).
METHODS: National surveillance data from Australia, Canada, Israel, England & Wales, and the United States (US) were included. All countries introduced PCV7 followed by PCV13 and reported serotype- and age-specific IPD incidence annually. For each age group (<2, 2-<5, and ≥65 years), we calculated the annual relative change in non-PCV13 type (NVT) IPD incidence compared to the year pre-PCV13 introduction.
RESULTS: Across countries, relative increases in NVT IPD were observed following the introduction of PCV13 in the NIP for those <2 years, ranging from a 20% increase in the US to 204% in Australia in year 7 (Figure 1). For age groups 2-<5 and ≥65 years, NVT trends were variable across countries. The US, England & Wales, and Australia observed little to no serotype replacement in those 2-<5 years, whereas Israel and Canada observed relative increases of 89% to 110%, respectively. In those ≥65, the US observed a slight decrease in NVT disease, and other countries observed increases over 41%.
CONCLUSIONS: For most countries, NVT increases were observed across age groups. Broader PCV serotype coverage is needed to address NVT IPD. PCV20 is in advanced clinical development for pediatric populations and has seven additional serotypes beyond PCV13 that can help reduce current NVT burden.
