[Epidemiological characteristics of human metapneumovirus and risk factors for severe pneumonia in hospitalized children].

OBJECTIVES: To investigate the epidemiological characteristics of human metapneumovirus (hMPV) and the risk factors for severe pneumonia in hospitalized children. METHODS: The epidemiological characteristics of hMPV in hospitalized children at Hebei Children's Hospital from January 2019 to December 2023 were retrospectively analyzed. The clinical data of hospitalized children with hMPV infection from April to December 2023 were included, and independent risk factors for severe pneumonia were identified through logistic regression. RESULTS: A total of 44 092 children were tested, with an hMPV positive rate of 7.30% (3 220/44 092). Children aged 3-6 years constituted the largest proportion (40.93%, 1 318/3 220) among hMPV-positive cases. The detection rate varied significantly by year (P<0.001), peaking in 2022 (12.35%, 978/7 919). The peak season of the epidemic was winter and spring from 2019 to 2021, but shifted to spring and summer from 2022 to 2023. The proportion of co-infection was 38.70% (1 246/3 220), primarily with rhinovirus (600/1 246, 48.15%), Mycoplasma pneumoniae (217/1 246, 17.42%), and respiratory syncytial virus (182/1 246, 14.61%). The main manifestations of hMPV pneumonia were cough, expectoration, and fever. Children with severe pneumonia were significantly younger (P<0.05). Wheezing, underlying diseases, co-infection, and younger age were identified as independent risk factors for severe pneumonia (P<0.05). CONCLUSIONS: There are significant annual and seasonal differences in the epidemiological characteristics of hMPV in hospitalized children. Young age, underlying diseases, wheezing, and co-infection are independent risk factors for severe pneumonia.