Invasive Pneumococcal Disease in Argentine Children After Widespread PCV13 Use: Burden, Potential PCV20 Coverage and Mortality Risk Factors Across Three Years of Surveillance.

BACKGROUND

In Argentina, widespread 13-valent pneumococcal conjugate vaccine (PCV13) use has reshaped pediatric invasive pneumococcal disease (IPD) epidemiology, with ongoing serotype shifts. We assessed IPD burden, clinical and microbiological features, PCV20 coverage, and mortality risk factors.

METHODS

Multicenter prospective observational study based on active surveillance, conducted in 6 pediatric sentinel hospitals (October 2022-September 2025). Children ≤15 years hospitalized with laboratory-confirmed IPD were included. Hospitalization rates per 10,000 discharges were calculated with 95% confidence intervals (CIs). Mortality risk factors were assessed using logistic regression.

RESULTS

Among 136,018 hospital discharges, 218 IPD cases were identified (16.0 per 10,000; 95% CI, 14.0-18.3; 0.16% of hospitalizations), with the highest rates in children aged 2-4 years (26.5 per 10,000; 95% CI: 20.6-33.5). Half (45.9%) had underlying conditions. Pneumonia predominated (65.6%), often complicated by pleural effusion/empyema or necrotizing disease, and 18.9% required mechanical ventilation; meningitis occurred in 14.7%. Among 119 serotyped isolates, 30.3% were PCV13, 21.0% additional PCV20 and 48.7% non-PCV20 serotypes, yielding an estimated PCV20 coverage of 51.3%. All isolates were ceftriaxone-susceptible; penicillin resistance (4.6%) was limited to meningitis. Case fatality was 5.0%. In multivariable analysis, sepsis (adjusted odds ratio [aOR] 20.82; 95% CI: 4.23-102.58) and meningitis (aOR 10.75; 95% CI: 2.10-54.95) were strongly associated with mortality.

CONCLUSIONS

In the late PCV13 era, pediatric IPD in Argentina remains clinically severe and shows marked serotype replacement. PCV20 increases coverage to approximately half of circulating serotypes. Sepsis and meningitis remain key mortality determinants, underscoring the need for early recognition, timely treatment, improved vaccination coverage and continued surveillance to assess PCV20 impact.