Evolving Landscape of Paediatric Pneumococcal Meningitis in Argentina (2013-2023)

The introduction of pneumococcal conjugate vaccination (PCV) into the Argentinian Childhood National Immunization Program in 2012 marked a significant milestone in public health. Our study aims to assess the impact of this intervention on pneumococcal meningitis cases, serotype distribution, and antimicrobial resistance among paediatric populations from 2013 to 2023. Specifically, we compared the early post-PCV period (2013–2014) to the late post-PCV period (2022–2023). A total of 333 pneumococcal isolates were analyzed between 2013 and 2023. Gold standard pneumococcal serotyping was performed to identify the serotypes associated with infection in children < 6 years in Argentina and agar dilution method was carried out to determine their profiles to antimicrobial agent. Our findings underscore the importance of PCV implementation, revealing notable shifts in pneumococcal epidemiology over the study period: proportion of serotypes 1 (6.7% to 0.0%), 5 (5.6% to 0.0%) and 14 (7.8% to 1.8%) decreased, whereas proportion of serotypes 10A (3.3% to 10.7%), 15B/C (2.2% to 10.7%) and 24B (0.0% to 8.9%) increased The top five rated serotypes in the 2022-2023 period were serogroup 24 (21.4%), 10A (10.7%), 15B/C (10.7%), 23B (7.1%) and 12F (5.4%). Regarding antimicrobial resistance, we found that a total of 115/311 isolates (37%) were non suceptible to penicillin, 2.9% to cefotaxime. Twenty five percent of the isolates were microbial drug resistant, with resistance to penicillin, erythromycin, tetracycline/doxicycline and/or cotrimoxazol. Among PCV13 serotypes, 19A remained the most commonly associated with MDR. Non-PCV13 serotypes, particularly 24F, 24A, and 24B, were prevalent among MDR isolates. The observed trends advocate for the continued expansion of pneumococcal vaccination policies, including consideration for vaccines offering enhanced indirect protection, thereby extending benefits beyond the paediatric population to encompass adults as well. Such strategies are pivotal in reducing the burden of pneumococcal disease and safeguarding public health.