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

UNLABELLED: 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 5 years and evaluate the potential impact of new vaccines (PCV15 and PCV20). A 5-year prospective observational study was conducted from 2018 to 2022, including children up to 18 hospitalized with IPD at three major children's hospitals in Catalonia. Data on clinical, epidemiological, and microbiological factors were collected. A total of 220 episodes were identified, with a median age of 33.0 months (range 0-209). Comparing pre-pandemic (2018-2019) to early pandemic years (2020-2021), the IPD rate in children < 18 years decreased by 60.6% (p < 0.001). 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%). Ninety-three 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.

WHAT IS KNOWN: • Serotype 3 remains a leading cause of invasive pneumococcal disease (IPD) despite inclusion in PCV13 due to its limited vaccine effectiveness. • IPD incidence decreased globally during the COVID-19 pandemic, likely due to public health measures.

WHAT IS NEW: • In Catalonia, serotype 3 continues to dominate pediatric IPD cases and is frequently associated with complicated pneumonia and vaccine failure. • PCV15 and PCV20 offer broader serotype coverage and may significantly improve IPD prevention in children.