Clinical manifestations, serotype distribution and incidence of pediatric invasive pneumococcal disease in Catalonia (Spain), 2018-2022.

Abstract

Purpose The global incidence of invasive pneumococcal disease (IPD) decreased after the switch from PCV7 to PCV13 in 2010. However, serotype 3 remains the leading cause of IPD in Catalonia (Spain), due to the low effectiveness of PCV13 against it. This study aimed to analyze the clinical, epidemiological, and microbiological characteristics of IPD in children over five years and evaluate the potential impact of new vaccines (PCV15 and PCV20). Methods A 5-year prospective observational study was conducted from 2018 to 2022, including children under 18 hospitalized with IPD at three major children’s hospitals in Catalonia. Data on clinical, epidemiological, and microbiological factors were collected. Results 220 episodes were identified, with a mean age of 43.9 months (SD 39). Comparing pre-pandemic (2018-2019) to early pandemic years (2020-2021), the IPD rate in children <18 years decreased by 60.6% (p<0.000). However, no significant change was observed when comparing 2022 to 2018. The most common diagnoses were pneumonia (61.8%), meningitis (14.5%), and bacteremia without focus (13.2%). Serotype 3 was the leading cause (35.1%) of IPD and was associated with complicated pneumonia (84.7%) and vaccine failure (73.6%). 93 IPD episodes (45.4%) were caused by PCV13 serotypes, 97 (47.3%) by PCV15 serotypes and 132 (64.4%) by PCV20 serotypes. Conclusion The incidence of IPD has remained stable, except for a decrease during the pandemic. Serotype 3 was the most common, often associated with vaccine failures and severe pneumonia. PCV15 and PCV20 vaccines could offer better coverage against circulating serotypes and further reduce IPD incidence in Catalonia.