Epidemiological Characteristics of Respiratory Syncytial Virus in Pediatric Acute Lower Respiratory Tract Infections in Baoding, Hebei Province of China, from 2017 to 2024

Objectives: To investigate the clinical and epidemiological characteristics of respiratory syncytial virus (RSV)-associated acute lower respiratory tract infection (ALRTI) among hospitalized children in the Baoding region of Hebei Province, China. Methods: The study subjects were inpatients diagnosed with ALRTI at a pediatric hospital in Baoding between 1 June 2017 and 31 December 2024. A retrospective analysis was conducted on the detection of RSV and other common respiratory viruses in respiratory specimens to evaluate the clinical epidemiological characteristics of RSV. Viral detection was performed using immunofluorescence (IF) or polymerase chain reaction (PCR) assays. Results: The overall RSV detection rate was 16.8% (4945/29,399), with 6.7% co-infections. The RSV detection rate was 29.8% (2604/8729) in infants younger than 1 year and 18% (942/5232) in the 1-year-old group, then showing a decreasing trend with increasing age, with the lowest rate of 3.8% (283/7366) observed in the ≥5 years age group. The RSV detection rate decreased from 19.9% before the COVID-19 pandemic (2017–2019) to around 13% during and after the pandemic (χ2 = 233.732, p < 0.001), accompanied by a drop in the proportion of children under 2 years from 78.5–79.6% before the COVID-19 pandemic to 42.1–51.1% after the pandemic period (χ2 = 387.565, p < 0.001). RSV seasonality shifted from a typical single winter–spring peak in the pre-COVID-19 era to a markedly reduced peak during the pandemic, in contrast to a delayed summer–autumn “off-season” pattern observed in the post-pandemic period. Conclusions: RSV remains the predominant pathogen for hospitalized ALRTI in Baoding, particularly among infants. Detection rates of RSV declined with increasing age. The COVID-19 pandemic has profoundly impacted RSV prevalence patterns and seasonality, underscoring the critical need for long-term surveillance.