Predominant Detection of the Subgroup A2b Human Metapneumovirus Strain with a 111-Nucleotide Duplication in the G gene in Yokohama City, Japan in 2018.

Human metapneumovirus (HMPV) has been a major causative agent of acute respiratory infections in humans. Recently, two types of variant A2b subtype HMPV strains possessing a 111- or 180-nucleotide duplication (nt-dup) in the G gene (HMPV A2b and HMPV A2b, respectively) were detected in Japan, Spain, Vietnam, and China. Our surveillance for infectious agents in Yokohama City, Japan revealed that the HMPV A2b strain became predominant in Yokohama City in 2018. In contrast, no classic HMPV A2b strain was detected after 2017. These data indicate a beneficial role of the 111nt-dup in the G gene for the transmission of HMPV.