Impact of the Sars-Cov-2 Pandemic on Streptococcus Pneumoniae Infections in a Tertiary Pediatric Hospital in Southern Brazil: A Pre- And Post-Pandemic Comparative Analysis

Streptococcus pneumoniae is a highly relevant bacterium, responsible for significant infectious morbidity and mortality in children. The COVID-19 pandemic altered the epidemiological patterns of pediatric respiratory infections and may have favored the emergence of resistant bacteria. This study evaluated the clinical, microbiological and therapeutic profile of S. pneumoniae infections in hospitalized children in a tertiary hospital in Southern Brazil, comparing pre-pandemic (2018–2021) and post-pandemic (2022–2024) periods, to assess the possible impacts and improve therapeutic strategies and public policies related to vaccination and antimicrobial resistance control. A retrospective, observational, analytic study was conducted including patients hospitalized for more than 24 hours with positive cultures for S. pneumoniae between January 2018 and December 2024. A total of 126 medical records were reviewed; incomplete records and colonization cultures were excluded. Clinical, epidemiological, microbiological, therapeutic data and outcomes were collected. Descriptive analysis and chi-square tests were used, with p<0.05 considered significant. The final sample comprised 120 patients, mostly under two years of age (45.8%), and over 60% were previously healthy. Vaccination records were inadequate in both periods: only 9.2% had documented vaccination status, dropping to 2.4% in the post-pandemic period. Approximately 66% of cases showed antimicrobial resistance, mainly to sulfamethoxazole-trimethoprim (57%) and clindamycin (56%), with no significant difference between periods. The main diagnosis was pneumonia (60.8%), and there was no significant difference in infection site or length of stay. However, there was a trend toward greater severity post-pandemic: increased ICU admissions (66.3% vs. 48.6%) and length of stay >15 days (51.8% vs. 43.2%). S. pneumoniae maintained its resistance and pathogenicity patterns even after the pandemic. Although statistical significance was not reached, the trend toward greater severity in the post-pandemic period reinforces the need for continuous surveillance, and the low vaccination documentation highlights the importance of strengthening immunization campaigns. Overall, the study underscores the importance of rational antimicrobial use and epidemiological surveillance for effective control of pneumococcal infections in children.