Outcomes of pediatric community-acquired pneumonia before and after national pneumococcal immunization in Taiwan

Objective: In Taiwan, the incidence of invasive pneumococcal disease (IPD) in children declined after the catch-up primary vaccination programs and the full national immunization program (NIP) with PCV13. The objective of the study was to investigate the clinical outcomes of pediatric community-acquired pneumonia (CAP) before and after the NIP. Methods: The study included patients aged 3 months to 17 years who were diagnosed with CAP and treated at the National Taiwan University Hospital between 2007 and 2019. Patients were assigned to three birth cohorts according to their birth years and vaccination eligibility: non-NIP, catch-up, and full NIP. We compared the rates of severe outcomes, including case fatality and pathogens. Results: A total of 6557 patients who met the CAP criteria were enrolled during the study period. The case-fatality rate decreased from 3.2% (94/2984) in the non-NIP cohort to 0.3% (7/2176) in the catch-up cohort and 0.8% (11/1397) in the full NIP cohort (p < 0.001). Furthermore, there was a significant decrease in invasive ventilation from the non-NIP (17.9%) to both catch-up (6.8%) and full NIP cohorts (9.1%). The rate of IPD declined from the non-NIP cohort to the catch-up cohort (1.8% vs. 0.6%, p < 0.001) and from the catch-up to the full NIP cohort (0.6% vs. 0.07%, p = 0.014). In contrast, the rates of infections with other pathogens increased after NIP. Conclusion: The introduction of PCV13 showed significant reduction in case-fatality and IPD rates. The increasing rates of other pathogens warrant further surveillance for their clinical significance.