Epidemiological characteristics and whole-genome analysis of respiratory syncytial virus in Jining city from February 2023 to December 2024

Background: Respiratory syncytial virus (RSV) is a major viral pathogen causing respiratory tract infections in children, often leading to bronchiolitis, pneumonia, and even death. This study aimed to investigate the epidemiological patterns and whole-genome characteristics of RSV circulating in Jining city between February 2023 and December 2024. Methods: From February 2023 to December 2024, a total of 5,042 throat swab samples were collected from influenza-like illness (ILI) cases at two sentinel hospitals in Jining. RSV was detected using reverse transcription quantitative real-time PCR (RT-qPCR). RSV-positive samples were subjected to whole-genome sequencing. Phylogenetic trees were constructed based on the whole genome and G gene sequences, and antigenic variation in viral proteins was analyzed. Results: RSV positivity was 1.98% (100/5042), with higher rates in children under 5 years of age. RSV activity peaked in April-May 2023 and December 2023-January 2024. A total of 29 RSV genomes were sequenced, including 18 RSV-A and 11 RSV-B. RSV-A was dominant during the first peak, and RSV-B during the second. Most RSV-A strains belonged to clade AD.3 and genotype ON1; RSV-B strains clustered into clades B.D.E.1, B.D.4.1.1, and B.D.E.2, all within genotype BA9. Mutations were identified in antigenic epitopes of the G and F proteins, including amino acid substitutions and changes in glycosylation and phosphorylation sites. Conclusion: RSV-A and RSV-B circulated in Jining in an alternating pattern, with evidence of ongoing antigenic evolution. Continued RSV surveillance and accelerated vaccine development are essential.