The microbiological characteristics and diagnosis of Streptococcus pneumoniae infection in the conjugate vaccine era

Abstract

Two pneumococcal conjugate vaccines, PCV15 and PCV20, were licensed in June 2021. PCV15 includes two additional serotypes (22F, 33F) beyond those in PCV13, while PCV20 adds seven more (8, 10A, 11A, 12F, 15B, 22F, 33F), covering approximately 30% of invasive pneumococcal disease (IPD) cases in adults. In June 2023, the US CDC’s Advisory Committee on Immunization Practices (ACIP) recommended either PCV15 or PCV20 for all children aged < 5 years and children aged 2‒18 years with risk conditions. In June 2024, the FDA approved PCV21 for adults ≥ 18 years. In October 2024, ACIP recommended either PCV20 or PCV21 alone or PCV15 with PPSV23 for adults ≥ 50 years or 19–49 years with risk conditions. These advancements highlight the evolving landscape of pneumococcal vaccination. This review examines the molecular epidemiology of pneumococcal infections, advancements in diagnostic methods, and the anticipated public health impact of these vaccines in reducing pneumococcal disease burden.