Abstract
Respiratory infections are a leading cause of hospitalization and mortality in children, and the pediatric intensive care unit (PICU) is a critical setting for managing severe cases. However, the epidemiological patterns of respiratory pathogens in the PICU remain insufficiently characterized. In this retrospective study, we analyzed respiratory pathogen testing results from 2126 pediatric patients admitted to the PICU of Wuhan Children's Hospital between 2019 and 2024. The pathogen spectrum and epidemiological characteristics were evaluated across age groups and seasons. Respiratory syncytial virus (RSV, 18.06%) was the most frequently detected viral pathogen, while Streptococcus pneumoniae (6.96%) was the predominant non-viral pathogen. The overall infection burden was highest in children aged ≤ 1 year (53.75%) and 3 < age ≤ 6 years (54.70%), indicating that early childhood represents a high-risk period for severe respiratory infections requiring intensive care. Pathogen distribution varied significantly across age groups. Distinct seasonal patterns were observed for several respiratory pathogens, particularly among viral pathogens, whereas non-viral pathogens showed more variable seasonal distributions. Furthermore, screening for 10 common pathogens accounted for 75% of PICU respiratory infections, highlighting the clinical utility of multiplex molecular detection. This study delineates the pathogen spectrum of respiratory tract infections in the PICU and characterizes their age- and season-specific epidemiological patterns. This study defines the pathogen spectrum and age- and season-specific patterns of respiratory infections in the PICU, providing evidence to support targeted pathogen surveillance, optimized multiplex diagnostics, and risk-informed infection control strategies in pediatric critical care.