The impact of the COVID-19 pandemic on respiratory viruses in hospitalized children with lower respiratory tract infections in Suzhou, southeast of China

Abstract Background The coronavirus disease 2019 (COVID-19) pandemic has led to the use of multifaceted non-pharmaceutical interventions (NPIs) to mitigate disease spread. NPIs also have an impact on the prevalence of non-SARS-CoV-2 viruses. We aimed to explore the prevalence of common respiratory viruses among hospitalized children with lower respiratory tract infections (LRTIs) in Suzhou, southeast China, during the COVID-19 pandemic. Methods Medical records and nasopharyngeal specimens of children hospitalized with LRTIs in the Children's Hospital of Soochow University from 2018 to 2021 were collected. Seven common respiratory viruses, namely, respiratory syncytial virus (RSV), adenovirus (ADV), influenza virus types A and B (IV-A and IV-B), parainfluenza virus types 1, 2, and 3 (PIV l to 3), were detected by direct immunofluorescence. Fluorescent quantitative PCR was performed to detect Bocavirus (HBoV), and reverse transcription-polymerase chain reaction (RT‒PCR) was performed to detect human respiratory rhinovirus (HRV) and human metapneumovirus (HMPV). Results A total of 13873 children including 8429 (60.8%) patients in 2018-2019 and 5444(39.2%) patients in 2020-2021 were enrolled. The total detection rate of respiratory viruses was 40.2% in 2018-2019 and 39.9% in 2020-2021. There was a high prevalence of HRV in June-September 2020 (after the reopening of schools), which was higher than the prevalence observed in June-September in 2018 and 2019. The detection rate of RSV decreased sharply in February 2020. After the schools were fully reopened in September 2020, the number of RSV cases gradually increased and peaked in December 2020 and January 2021.From July-September 2021, there was an unexpected mini-peak of RSV. The prevalence of IV decreased significantly after the COVID-19 epidemic, especially IV-A, but there were no significant changes in the age of infection and the epidemic season. HBoV, HMPV, PIV1~3, and ADV showed different degrees of changes in the detection rate and season of infection before and after the COVID-19 epidemic. Conclusions During the COVID-19 pandemic, the detection rates of common respiratory viruses in Suzhou, southeast China, have changed differently with strict NPIs. Understanding the changes in the detection of respiratory pathogens after the epidemic will help clinicians develop early coping strategies. Key words: COVID-19, children, respiratory viruses, NPIs, viral interference