Epidemiology of respiratory pathogens in patients with acute respiratory infections during the COVID-19 pandemic and after easing of COVID-19 restrictions.

We aimed to investigate the epidemiological characteristics of non-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) respiratory pathogens among patients with acute respiratory infections (ARIs) in Shijiazhuang, China, during the coronavirus disease 2019 (COVID-19) pandemic (January 2021--December 2022) and after the relaxation of COVID-19 restrictive measures (January 2022--December 2023). This retrospective study enrolled 6,633 ARIs patients who visited the Hebei General Hospital between 2021- and 2023. Nasopharyngeal swabs samples were collected for multiplex PCR detection of 13 common respiratory pathogens. Respiratory pathogens were detected in 31.58% of individuals diagnosed with ARIs, whileereas a co-infection with multiple pathogens was observed in 8.5% of the ARI patients. In the years 2021 and 2022, 326 (27.63%) and 283 (24.38%) respiratory pathogens were found to be positive, respectively, during the COVID-19 pandemic. However, in 2023, subsequent to the easing of COVID-19 restrictions, the positivity rate significantly rose to 34.62%, with 4,292 cases identified. The majority of positive cases over the last three3 years were concentrated in patients under 14 years old. The predominant pathogens identified were human rhinovirus (HRVs) (15.08%) in 2021, mycoplasma pneumonia (MP) (6.46%) in 2022, and influenza A virus (FluA) (11.35%) in 2023. Seasonal prevalence patterns of most pathogens were affected, except for parainfluenza virus (PIV). There was a simultaneous increase in the positive cases and positivity rates of FluA and adenovirus (ADV) Iin 2023, compared to 2021 and 2022. Additionally, the infection rates of respiratory syncytial virus (RSV), MP, and coronavirus (CoV) in 2023 either exceeded or were comparable to those in 2021 and 2022. Conversely, the positivity rates of PIV, RVs, metapneumovirus (MPV), and influenza B virus (FluB) were lower in 2023 compared to 2021 or 2022.

Importance: The implementation of strict non-pharmaceutical interventions (NPIs) during the coronavirus disease 2019 (COVID-19) pandemic may lead to changes in the epidemiological features of respiratory pathogens, as well as the occurrence of immune debt, potentially causing a resurgence in respiratory pathogen activity following the easing of strict NPIs measures. There are limited reports on the epidemiological characteristics of respiratory pathogens among patients of all ages with acute respiratory infections (ARIs) during the COVID-19 pandemic and after the easing of COVID-19 restrictions. Our study investigated the epidemiology of 13 respiratory pathogens in Shijiazhuang, China, from January 2021 to December 2023. Thisese data isare crucial for the ongoing surveillance of epidemiological shifts in respiratory pathogens during and post the -COVID-19 pandemic, and serves as a scientific foundation for the prevention and management of ARIs.