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 A2b180nt-dup and HMPV A2b111nt-dup, respectively) were detected in Japan, Spain, Vietnam, and China. Our surveillance for infectious agents in Yokohama City, Japan revealed that the HMPV A2b111nt-dup 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.