Distinct molecular evolution of influenza H3N2 strains in the 2016/17 season and its implications for vaccine effectiveness

Mol Phylogenet Evol. 2019 Feb:131:29-34. doi: 10.1016/j.ympev.2018.10.042. Epub 2018 Nov 3.

Abstract

Influenza virus is a respiratory pathogen that causes seasonal epidemics by resulting in a considerable number of influenza-like illness (ILI) patients. During the 2016/17 season, ILI rates increased unusually earlier and higher than previous seasons in Korea, and most viral isolates were subtyped as H3N2 strains. Notably, the hemagglutinin (HA) of most Korean H3N2 strains retained newly introduced lysine signatures in HA antigenic sites A and D, compared with that of clade 3C.2a vaccine virus, which affected antigenic distances to the standard vaccine antisera in a hemagglutination inhibition assay. The neuraminidase (NA) of Korean H3N2 strains also harbored amino acid mutations. However, neither consistent amino acid mutations nor common phylogenetic clustering patterns were observed. These suggest that Korean H3N2 strains of the 2016/17 season might be distantly related with the vaccine virus both in genotypic and phenotypic classifications, which would adversely affect vaccine effectiveness.

Keywords: Hemagglutinin; Influenza; Molecular evolution; Neuraminidase; Vaccine effectiveness.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Evolution, Molecular*
  • Genotype
  • Hemagglutinin Glycoproteins, Influenza Virus / chemistry
  • Hemagglutinin Glycoproteins, Influenza Virus / genetics
  • Humans
  • Influenza A Virus, H3N2 Subtype / genetics*
  • Influenza Vaccines / immunology*
  • Models, Molecular
  • Mutation / genetics
  • Neuraminidase / chemistry
  • Neuraminidase / genetics
  • Phylogeny
  • Seasons*

Substances

  • Hemagglutinin Glycoproteins, Influenza Virus
  • Influenza Vaccines
  • Neuraminidase