[Analysis of clinical and epidemiological characteristics of pediatric lower respiratory tract infections caused by respiratory syncytial virus in Suzhou from 2018 to 2023].

<b>Objective:</b> To analyze the differences in clinical and epidemiological characteristics of lower respiratory tract infections caused by respiratory syncytial virus (RSV) in children in Suzhou area from 2018 to 2023. <b>Methods:</b> This study is a cross-sectional analysis. Children with lower respiratory tract infections who were hospitalized in the Children's Hospital of Soochow University from January 2018 to June 2023 and were clearly diagnosed with RSV infection were selected as subjects of this study. The clinical data of children who met the inclusion criteria during the epidemic period of RSV were collected, and the epidemic trend and clinical characteristics of RSV in different years were compared. RT-PCR was used to identify the subtypes of RSV A/B, and MEGA7 software was used for gene alignment after target gene amplification to analyze the typing and genotype characteristics of RSV in the peak epidemic period in 2023. <b>Results:</b> A total of 8 148 children were included in the study, among whom 1 043 were RSV-positive. The median age was 9 months (IQR: 3, 27). The proportion of children with isolated RSV infection in 2023 (35.9%, 82 cases) was lower than in 2019 (54.8%, 119 cases) and 2021 (51.2%, 167 cases) (<i>P</i><0.05). Compared to other years, children with isolated RSV infection in 2023 were older (<i>P</i><0.001), with a median age of 21.1 months (IQR: 7.3, 37.7), and the proportion in the 0-2 months age group was lower (9.7%, 8 cases) (<i>P</i><0.05), while the proportion in the 2-4 years age group was higher (30.5%, 25 cases). In terms of clinical manifestations, the proportion of febrile children in 2023 was higher (81.9%, 68 cases) (<i>P</i><0.001), while the proportion with high fever (66.2%, 45 cases) was lower than in 2020 (47.2%, 17 cases) (<i>P</i><0.05), and the proportion with low-grade fever (4.4%, 3 cases) also decreased compared to 2020 (27.8%,10 cases) (<i>P</i><0.05). The proportions of wheezing (42.7%, 35 cases) and dyspnea (2.4%, 2 cases) in 2023 were both lower than those in 2018 (71.0%, 49 cases) and (13.0%, 9 cases) (<i>P</i><0.05). The proportion of children with wheezing and crackles upon lung auscultation in 2023 (39.1%, 32 cases) was also lower than in 2018 (62.3%, 43 cases) (<i>P</i><0.05). In 2023, the predominant RSV subtype in the Suzhou area was Type A, with the main genotype being ON1. <b>Conclusions:</b> Compared to the clinical and epidemiological characteristics of RSV infections in Suzhou children from 2018 to 2023, the proportion of isolated RSV infections decreased in 2023, with a notable increase in age. Clinical manifestations are predominantly characterized by high fever, while respiratory symptoms are less severe, and the dominant viral strain is the A subtype of genotype ON1.