Epidemiology of respiratory infections during the different levels of non-pharmaceutical interventions.

Objective: This study aimed to describe epidemiological changes of common respiratory pathogens in children with acute respiratory infections (ARIs) during the different levels of non-pharmaceutical interventions(NPIs).

Methods: In this retrospective study, we analyzed the prevalence of 12 respiratory pathogens from September 2021 through February 2024 in all inpatients with ARIs admitted to Children's Hospital of Soochow University(SCH). We compared the detection rates of these pathogens at different levels of public NPI measures.

Results: In total, 27,851 respiratory samples were analyzed, including 15,231 boys and 12,620 girls. Under strict NPIs, inpatients with ARIs were more commonly boy and infants (p < 0.01). However, after the discontinuation of NPIs, they were more commonly children over 6 years of age (p < 0.01). Under the strict NPIs, the most detected respiratory pathogen was HRV(23.6%), followed by HRSV(16.0%), HMPV(10.8%) and HPIV(10.4%). But after the abolition strict NPIs, the most common respiratory pathogen was MP(35.9%), followed by HRV(19.7%), HRSV(17.5%) and HPIV (6.6%). Moreover, the number and detection rate of MP and ADV had significantly increased and remained at a high level (P<0.05). In addition, the number of HRSV detection increased and the epidemic season has changed(transitioning from winter to summer), and detection rate of multiple pathogens was more high after the abolition NPIs (P < 0.01).

Conclusions: Withdrawal of major measures, the disease burden of ARIs in children in Suzhou has sharply increased, mainly attributed to MP, and mixed infections were more common.