Epidemiological, Clinical, and Genomic Traits of PIV in Hospitalized Children After the COVID-19 Pandemic in Wuhan, China

Human parainfluenza virus (PIV) is a main cause of acute lower respiratory tract infections (ALRTIs), which contributes to childrens' mortality worldwide; however, the epidemiology of PIVs following the SARS-CoV-2 pandemic is still not clarified, and poses risks of potential outbreaks. Herein, we conducted a retrospective observational study from September 26, 2020 to September 30, 2023 to assess PIV epidemiology in Wuhan, China, as well as the clinical characteristics of PIV infections. In total, 14,065 inpatients with ALRTIs were enrolled, of which 936 were identified to have PIV infection. We also obtained 69 PIV3 RNA to reveal its molecular traits. An alteration in PIV season pattern away from spring and summer prevalence was noted, as well as a progressive rise in its detection rate. PIV-related ALRTIs were more prevalent in male patients. PIV3 was the dominant PIV type in recent years. In comparison with the phase before the cancellation of Dynamic Zero-COVID Policy in December 2022, symptoms after its repeal were milder. All Wuhan strains were classified with C3f lineage and possibly evolved from native strains in China. Additionally, some mutations, such as Q499P in protein hemagglutinin-neuraminidase, should be given further attention. In summary, our study demonstrates the clinical characteristics of PIVs and genomic traits of PIV3 in Wuhan, China, thus holds importance for the diagnosis and control of PIV infections in the post-pandemic era.