[Analysis of respiratory syncytial virus infection among hospitalized children with acute respiratory tract infections in Hangzhou City, 2023-2024].

Objective: To investigate the epidemiological characteristics of respiratory syncytial virus (RSV) infection among hospitalized children with acute respiratory infections (ARIs) in Hangzhou from 2023 to 2024. Methods: From March 2023 to February 2025, a study was conducted among hospitalized children with ARIs at Hangzhou Children's Hospital. Respiratory specimens were collected and tested using multiplex real-time quantitative PCR (qPCR) to detect RSV and five other common respiratory pathogens, including influenza A virus, influenza B virus, adenovirus (ADV), parainfluenza virus type 3 (PIV3), and parainfluenza virus type 1 (PIV1). Demographic data were also collected to analyze the epidemiological characteristics of RSV infection. Results: A total of 31 234 hospitalized children with respiratory tract infections were included, among whom 2 944 tested positive for RSV, yielding a positive rate of 9.43%. Of these, 248 cases were co-infections, with a co-infection rate of 8.42%. The positive rate of RSV was 11.18% (1 606/14 366) in 2023 and 7.93% (1 338/16 868) in 2024, with a statistically significant difference (P<0.001). Among co-infections, RSV-adenovirus co-infection was the most common (2.99%, 88/2 944), followed by RSV-PIV3 co-infection (2.51%, 74/2 944). An atypical off-season surge of RSV was observed during the summer of 2023. The positive rate of RSV showed a decreasing trend with age (P<0.001). The positive rate of RSV in lower respiratory tract infections was 12.46%, significantly higher than that in upper respiratory tract infections (2.52%) (P<0.001). Conclusion: The positive rate of RSV among hospitalized children with ARIs in Hangzhou from 2023 to 2024 is relatively low. Co-infections are mainly associated with adenovirus and parainfluenza virus type 3. The epidemiology of RSV varies by age and season.