[Analysis of seroepidemiological characteristics of 11 common respiratory pathogens infection based on 35 665 screened individuals].

Objective: To analyze the seroepidemiological characteristics of common respiratory pathogens in patients screened at a tertiary hospital in Zhangjiakou from 2018 to 2024. Methods: This single-center cross-sectional study utilized data from the laboratory information management system (LIS) of The First Affiliated Hospital of Hebei North University. We collected clinical data and serum-specific IgM antibody test results for 11 common respiratory pathogens (influenza A virus, influenza B virus, respiratory syncytial virus, parainfluenza virus, mycoplasma pneumoniae, chlamydia pneumoniae, legionella pneumophila, coxsackie A virus, coxsackie B virus, echovirus and adenovirus), excluding SARS-CoV-2, from January 1, 2018, to December 31, 2024. Comparative analyses were conducted across three periods: 2018-2019, 2020-2022, and 2023-2024. Statistical analyses were performed using SPSS 26.0, with categorical data presented as percentages and compared using χ² tests. Results: From 2018 to 2024, a total of 35 665 patients with respiratory tract infection were screened, of which 10 531 were positive for at least one pathogen, with a total positive rate of 29.53% (10 531/35 665). Age-adjusted positive rates were highest in 2023-2024 compared to 2018-2019 and 2020-2022 (χ²=690.789, P<0.001). The specific data are as follows: 21.35% (2 476/11 598) in 2018-2019, 24.35% (2 942/12 081) in 2020-2022, and 35.73% (4 283/11 986) in 2023-2024. Among the 11 pathogens, mycoplasma pneumoniae had the highest overall positivity rate (11.99%, 4 278/35 665), followed by influenza B virus (10.83%, 3 861/35 665), the other nine pathogens showed lower rates (0.88%-4.97%). At different time stages, the positive rates of serum IgM antibodies of various pathogens showed different changing characteristics: in 2023-2024, the positive rates of serum specific IgM antibodies against mycoplasma pneumoniae, influenza B/A virus and adenovirus increased significantly compared with those in 2020-2022, from 10.35%, 11.91%, 3.68%, 0.43% to 12.11%, 14.97%, 5.37%, 4.43% respectively (χ²=59.150, P<0.001; χ²=579.484, P<0.001; χ²=116.263, P<0.001; χ²=654.125, P<0.001). The positive rates of serum IgM antibody in patients of different age groups also showed different changing trends. In 2023-2024, the proportion of people in 18 to 60 and ≥60 age groups increased compared with that in 2018-2019 (χ²=325.069, P<0.001; χ²=593.612, P<0.001), while the 0 to 3, 3 to 6, and 6 to 12 age groups showed declines (χ²=382.067, P<0.001; χ²=252.835, P<0.001; χ²=285.888, P<0.001). Regarding the composition of serum IgM antibodies in different infection patterns, the proportion of single-pathogen infections decreased in 2023-2024 compared with that in 2018-2019 (χ²=130.19, P<0.001), while the proportion of two and three pathogen co-positive increased (χ²=65.533, P<0.001; χ²=46.836, P<0.001).The most common single-pathogen infections were mycoplasma pneumoniae, influenza B/A virus and legionella pneumophila; the predominant dual-pathogen combinations were influenza A+B viruses, influenza B virus+mycoplasma pneumoniae, and mycoplasma pneumoniae+legionella pneumophila. Conclusion: From 2018 to 2024, the seroepidemiological characteristics of common respiratory pathogens changed significantly with different time stages. The positive rate of serum-specific IgM antibodies were influenced by the social environment and public health intervention measures. Serological testing is an important means for the monitoring of respiratory pathogens and the prevention and control of infections in this region.