Abstract
BACKGROUND: The COVID-19 pandemic and associated non-pharmaceutical interventions significantly altered the epidemiology of respiratory pathogens. This study aimed to evaluate the changes in the prevalence and distribution of respiratory pathogens among children with acute respiratory infections (ARIs) before and after the relaxation of COVID-19 restrictions in Shenzhen, China. METHODS: This study enrolled hospitalized children with ARIs in Shenzhen Children's Hospital during the COVID-19 epidemic and those post-epidemic period. Demographic data of the patients enrolled were retrieved from the Shenzhen Children's Hospital electronic patient dossiers. Nasopharyngeal swabs were collected and detected for 11 pathogens, and epidemiological trends were analyzed by age, season, and pathogen distribution. RESULTS: A total of 40,174 children with ARIs were enrolled, including 14,816 during the COVID-19 epidemic and 25,358 in the post-epidemic period. Hospital admissions for ARIs increased by 71.2% in the post-epidemic period. The median age of patients rose from 27 to 47 months. Pathogen detection rates increased significantly from 59.3% during epidemic period to 73.0% in post-epidemic period (p < 0.001), with co-detection (≥ 2 pathogens) rising from 10.5% to 21.2%. The dominant pathogens shifted from HRV, RSV, and HPIV during COVID-19 epidemic to HRV, MP, and RSV in the post-epidemic. Notably, MP detection rates surged from 1.69% to 20.87%, while RSV and HPIV peaks were replaced by MP and HMPV in winter. CONCLUSION: The relaxation of COVID-19 non-pharmaceutical interventions led to a significant rebound in ARIs among children, with altered pathogen dominance and increased co-detection.