Emergence and #antigenic characterisation of #influenza #H3N2 viruses with #hemagglutinin substitutions N158K and K189R during the 2024/25 influenza season
Abstract Background Seasonal human influenza viruses can escape from antibody-mediated neutralization when amino acid changes occur in the hemagglutinin protein . Routine surveillance identified circulation of an A(H3N2) virus variant in the Netherlands with amino acid substitutions at hemagglutinin positions 158 and 189 . These amino acid positions were previously responsible for antigenic change of influenza A(H3N2) viruses and potentially lead to escape of this variant from vaccine-mediated immunity . Aim To characterize the emergence and antigenic properties of N158K and K189R double substitution virus variants . Methods We analyzed the geographical and temporal dynamics of the double-substitution variant using a phylogeographic approach and used hemagglutination inhibition assays and antigenic cartography methods to map its antigenic properties. Results A(H3N2) viruses carrying K189R were first detected in Guatemala in June 2024,...