Objective To understand the prevalence of respiratory syncytial virus （RSV） infections among children hospitalized with severe acute respiratory infections （SARI） in Huzhou， Zhejiang Province， and to explore the epidemiological characteristics and influencing factors of RSV.

Methods Nasopharyngeal swab samples from children under 15 years of age， newly admitted to the Huzhou First People's Hospital from 2018 to 2022 and who met the SARI surveillance definition， were collected for respiratory virus nucleic acid testing. SPSS 25.0 and Excel 2016 software were used for statistical analysis of the data.

Results A total of 1 076 samples were tested for nucleic acids， with an overall positivity rate of 11.2%. The positivity rate of infants under 5 years old was relatively high （16.7%）. RSV infection showed a seasonal distribution， mainly concentrated in autumn and winter， with the highest positivity rate in December （22.3%）. A total of 23 cases of respiratory mixed infection were detected， with a mixed infection rate of 2.13%， among which 16 were RSV-related mixed infections. Logistic regression analysis indicated that season and age were risk factors for RSV infection.

Conclusion From 2018 to 2022， RSV showed different epidemiological characteristics across different ages and seasons in SARI cases in Huzhou， with significant differences， providing a scientific basis for future prevention of RSV infections.