Analysis of respiratory pathogen detection in hospitalized children with acute respiratory tract infections after ending the zero COVID policy

After ending the three-year zero COVID policy in China, the epidemiology of other respiratory pathogens has been affected. This study aimed to characterize of common respiratory pathogen infections in pediatric patients hospitalized for acute respiratory tract infections (ARTIs) in Suzhou before and after ending the zero COVID policy. Nasopharyngeal aspirates (NPAs) were obtained from children with ARTIs (aged ≤ 16 years) at the Children's Hospital of Soochow University for the detection of respiratory syncytial virus (RSV), influenza A (FluA), FluB, human parainfluenza virus (HPIV), adenovirus (ADV), human rhinovirus (HRV), bocavirus (BoV), human metapneumovirus (HMPV), and mycoplasma pneumoniae (MP). The data were compared between two periods: January 2020 to December 2022 (before ending the zero COVID policy) and January 2023 to May 2024 (after ending the zero COVID policy). Patients were divided into four groups: 0-2, ≥ 3-5, ≥ 6-10, and ≥ 11-16 years. A total of 42,379 patients were enrolled and the top four pathogens identified were MP, HRV, RSV and HPIV with positive rates of 20.2%, 19.5%, 15.1%, and 6.9%, respectively. A total of 28,352 positive cases were detected, with positive rates of 54.0% (n = 11,850/21,941) and 80.7% (n = 16,502/20,438) before and after ending the zero COVID policy, respectively. Total RSV, HRV, HPIV, and MP positivity increased by 27.8%, 39.0%, 12.3%, and 322.7%, respectively, after ending the zero COVID policy compared to positivity before the policy. After ending the zero COVID policy, the positive rates of RSV, HRV, and HPIV increased most in children aged 0-2 years, with increases by 88.8% (OR: 2.3, 95% CI: 2.2-2.5), 50.0% (OR: 1.6, 95% CI: 1.5-1.7), and 69.6% (OR: 1.8, 95% CI: 1.6-2.0), respectively. The greatest increase in MP positivity was 316.9% in the 3-5 years (OR: 5.5, 95% CI: 4.9-6.1). After ending the zero COVID policy, the RSV-positive rate increased most in summer, while HRV was predominantly circulated in spring and the MP-positive rate peaked in autumn. Ending the zero COVID policy facilitated the transmission of common respiratory pathogens in children. Post-pandemic surveillance and control of respiratory pathogens must be strengthened to reduce health risks.