A comprehensive analysis of serotype-specific invasive capacity, clinical presentations, and mortality trends of invasive pneumococcal disease.

Background: Pneumococcal conjugate vaccines (PCV) reduced invasive disease, but the overall prevalence of pneumococcal nasopharyngeal colonization among children has not changed significantly. Our knowledge of which serotypes, once colonized, hold a higher likelihood to cause invasive disease is limited.

Methods: Serotype-specific invasive capacity (IC) of Streptococcus pneumoniae was estimated using an enhanced population-based invasive pneumococcal disease (IPD) surveillance in children <7 years of age in Massachusetts and surveillance of nasopharyngeal (NP) colonization in selected Massachusetts communities in corresponding respiratory seasons.

Invasive Pneumococcal Disease After 2 Decades of Pneumococcal Conjugate Vaccine Use.

Objectives: We sought to describe the evolving epidemiology of invasive pneumococcal disease (IPD) among children in Massachusetts, United States, over the last 2 decades during which sequential 7-valent pneumococcal conjugate vaccines (PCV7) and 13-valent PCVs (PCV13) were implemented.

Methods: Cases of IPD in children aged <18 years were detected between 2002 and 2021 through an enhanced population-based, statewide surveillance system. Streptococcus pneumoniae isolates from normally sterile sites were serotyped and evaluated for antimicrobial susceptibility.