Background: Respiratory tract infections are among the most common causes of acute illnesses, with viruses accounting for the majority of cases, particularly in outpatient settings. Regression-based study designs have been commonly employed to estimate the burden of influenza; however, these estimates frequently suffer from a lack of timeliness, and numerous countries face limitations due to insufficient virological data. Specifically for the northern region of Anhui Province, the local profile and infection patterns of respiratory pathogens remain not well-documented. This study seeks to contribute to bridging these knowledge gaps. Methods: A total of 15,774 patients with acute respiratory tract infections treated at the First Affiliated Hospital of Bengbu Medical University from January 1, 2020, to December 31, 2022 were included. Associations between pathogen detection and demographic variables were analyzed. IgM antibodies against multiple respiratory pathogens were detected using serological methods. Paired serum and throat swab samples from 374 non-COVID-19 patients were tested using both IgM antibody assays and multiplex nucleic acid amplification to compare diagnostic efficacy. Results: The overall IgM antibody positivity rate was 24.45%, with annual rates of 17.58% in 2020, 28.66% in 2021, and 25.83% in 2022. The highest detection rate was for Mycoplasma pneumoniae (MP; 15.22%), followed by Influenza B virus (IFBV; 3.75%) and Legionella (LP; 2.15%). Seasonal detection rates were 21.62% in spring, 26.31% in summer, 29.83% in autumn, and 20.40% in winter. Females had a higher detection rate (26.06%) than males (23.05%). Detection rates by age group were 33.83% in children, 13.81% in adolescents, 3.39% in young adults, 14.61% in middle-aged individuals, and 19.39% in the elderly. Nucleic acid testing demonstrated a higher positivity rate compared with IgM antibody testing. Conclusion: The detection rate of pathogen-specific IgM antibodies in respiratory tract infections varies by year, season, sex, and age. Nucleic acid testing provides superior diagnostic sensitivity compared with IgM antibody detection and should be prioritized in clinical practice. Keywords: respiratory tract infections, immunoglobulin M antibody, nucleic acid tests, Mycoplasma pneumoniae , influenza virus
Wei et al. (Sun,) studied this question.