Influenza A(H3N2) virus exhibiting reduced susceptibility to baloxavir due to a polymerase acidic subunit I38T substitution detected from a hospitalised child without prior baloxavir treatment, Japan, January 2019

Euro Surveill. 2019 Mar;24(12):1900170. doi: 10.2807/1560-7917.ES.2019.24.12.1900170.

Abstract

In January 2019, two influenza A(H3N2) viruses carrying an I38T substitution in the polymerase acidic subunit (PA), which confers reduced susceptibility to baloxavir, were detected from epidemiologically unrelated hospitalised children in Japan. The viruses exhibited reduced susceptibility to baloxavir but were susceptible to neuraminidase inhibitors. Only one of the two children had been treated with baloxavir. An epidemiological analysis suggests possible transmission of the PA I38T mutant A(H3N2) virus among humans.

Keywords: Influenza virus; baloxavir acid; baloxavir marboxil; cap-dependent endonuclease inhibitor; drug resistance.

MeSH terms

  • Adolescent
  • Adult
  • Antiviral Agents / pharmacology*
  • Antiviral Agents / therapeutic use
  • Child
  • Dibenzothiepins
  • Drug Resistance, Viral / genetics*
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Influenza A Virus, H3N2 Subtype / drug effects
  • Influenza A Virus, H3N2 Subtype / genetics*
  • Influenza A Virus, H3N2 Subtype / isolation & purification
  • Influenza, Human / diagnosis
  • Influenza, Human / drug therapy*
  • Inpatients
  • Japan
  • Middle Aged
  • Morpholines
  • Oxazines / pharmacology*
  • Oxazines / therapeutic use
  • Polymerase Chain Reaction
  • Pyridines / pharmacology*
  • Pyridines / therapeutic use
  • Pyridones
  • Thiepins / pharmacology*
  • Thiepins / therapeutic use
  • Treatment Outcome
  • Triazines / pharmacology*
  • Triazines / therapeutic use
  • Young Adult

Substances

  • Antiviral Agents
  • Dibenzothiepins
  • Enzyme Inhibitors
  • Morpholines
  • Oxazines
  • Pyridines
  • Pyridones
  • Thiepins
  • Triazines
  • baloxavir