Impact of serotype variability in Streptococcus pneumoniae on the effectiveness of pneumococcal vaccines in children from Latin America

Abstract

Streptococcus pneumoniae infection remains one of the leading causes of childhood morbidity and mortality in Latin America, with high serotype variability posing a challenge to the effectiveness of vaccination programs. Objective: To assess the impact of Streptococcus pneumoniae serotype variability on the effectiveness of pneumococcal vaccines in children under five years of age in Latin America. Methods: A systematic review was conducted following PRISMA guidelines, involving database searches and selection of 22 studies published between 2019 and 2024, focusing on circulating serotypes and their response to PCV10, PCV13, PCV15, and PCV20. Results: The data revealed a predominance of serotypes such as 19A, 6C, 24F, and 3, with heterogeneous circulation across countries and a notable gap in vaccine coverage against emerging clones not included in current formulations. PCV13 showed limitations against serotypes 19A and 3, whereas projections for PCV20 indicated broader coverage (up to 82%).
Conclusion: Serotype variability directly affects vaccine effectiveness in the region; thus, updating immunization schedules based on local evidence and active serotype surveillance is recommended. The use of higher-valency vaccines such as PCV20 is proposed for future immunization programs.