Comparison of respiratory pathogen infections in hospitalized patients before and during the COVID-19 pandemic in Shanghai, China.

This study aimed to assess the impact of COVID-19 on the prevalence of respiratory pathogens among hospitalized patients with respiratory tract infections in Shanghai, China. Patients with acute respiratory infections (ARIs) hospitalized at Putuo Hospital, Shanghai University of Traditional Chinese Medicine from January 2017 to December 2022 were collected. Indirect immunofluorescence assay (IFA) was used to detect the IgM antibody of nine common pathogens, including Chlamydia pneumoniae (CP), Mycoplasma pneumoniae (MP), parainfluenza virus (PIV), respiratory syncytial virus (RSV), influenza virus A (FluA), influenza virus B (FluB), adenovirus (ADV), Legionella pneumophila (Lp), and Coxiella burnetii (Cb). A total of 24,933 eligible patients were enrolled. The overall detection rate of respiratory pathogens in the pre-outbreak group (2017-2019, 32.05%) was significantly higher than that in the outbreak group (2020-2022, 11.48%, P < 0.001). MP (16.03%), Lp (2.43%), FluB (1.73%), and PIV (1.64%) were the main pathogens. Positivity for MP, FluB, and PIV declined significantly, whereas the detection rate of Lp was increased (P < 0.05) during the 2020-2022 period compared with the 2017-2019 period. Children (73.21%) experienced a significantly higher infection rate than adolescents (65.35%), adults (25.20%), and older adults (15.40%). MP+PIV was the most common co-detection pattern. The detection of CP, MP, PIV, RSV, FluB, ADV, and Lp differed significantly between the two periods. From 2020 to 2022, the detection rates of CP, MP, PIV, RSV, FluB, and ADV decreased, whereas the detection of Lp increased. Knowledge of common pathogens' dynamics could serve as a reference for further prevention and control of ARIs.

This study leverages the changes in the common respiratory spectrum pre-pandemic and during the COVID-19 pandemic in hospitalized patients in Shanghai. These data may serve as a scientific foundation for the prevention and management of ARIs. Doctors and policymakers should pay attention to the changes in the epidemic trends and types of respiratory pathogens and maintain monitoring of respiratory pathogens to better control the prevalence of respiratory pathogens.