Epidemiological characteristics of human metapneumovirus among children in Nanjing, China

The objective of this study was to examine the molecular epidemiology and clinical characteristics of HMPV infection among children with ARIs in Nanjing.

The respiratory samples were collected from 2078 children (≤ 14 years) with acute respiratory infections and were tested for HMPV using real-time RT-PCR. Amplification and sequencing of the HMPV G gene were followed by phylogenetic analysis using MEGA 7.0.

The detection rate of HMPV among children was 4.7% (97/2078), with a concentration in those under 5 years of age. Notably, the peak season for HMPV prevalence was observed in winter. Among the 97 HMPV-positive samples, 51.5% (50/97) were available for characterization of the HMPV G protein gene. Phylogenetic analysis indicated that the sequenced HMPV strains were classified into three sublineages: A2c_{111nt − dup} (84.0%), B1 (2.0%), and B2 (14.0%).

There was an incidence of HMPV among hospitalized children during 2021–2022 in Nanjing with A2c_{111nt − dup} being the dominant strain. This study demonstrated the molecular epidemiological characteristics of HMPV among children with respiratory infections in Nanjing, China.