An outbreak of influenza A(H1N1)pdm09 antigenic variants exhibiting cross-resistance to oseltamivir and peramivir in an elementary school in Japan, September 2024

Euro Surveill. 2024 Dec;29(50):2400786. doi: 10.2807/1560-7917.ES.2024.29.50.2400786.

Abstract

An outbreak of influenza A(H1N1)pdm09 viruses exhibiting cross-resistance to oseltamivir and peramivir occurred in Yokohama, Japan, in September 2024. Among 24 students in a class, 11 were diagnosed with influenza or influenza-like illness, and viruses harbouring the NA H275Y and HA Q210H substitutions were isolated from four. Deep sequencing analysis confirmed the clonal spread of these mutants. Antigenic analysis revealed differences from the vaccine strain. Continued monitoring is crucial to assess the potential for further spread of these mutant viruses.

Keywords: antiviral; baloxavir; influenza; oseltamivir; peramivir; resistance.

MeSH terms

  • Acids, Carbocyclic*
  • Antiviral Agents* / pharmacology
  • Antiviral Agents* / therapeutic use
  • Child
  • Cyclopentanes* / pharmacology
  • Disease Outbreaks*
  • Drug Resistance, Viral* / genetics
  • Female
  • Guanidines* / pharmacology
  • Humans
  • Influenza A Virus, H1N1 Subtype* / drug effects
  • Influenza A Virus, H1N1 Subtype* / genetics
  • Influenza A Virus, H1N1 Subtype* / immunology
  • Influenza A Virus, H1N1 Subtype* / isolation & purification
  • Influenza, Human* / epidemiology
  • Influenza, Human* / virology
  • Japan / epidemiology
  • Male
  • Mutation
  • Neuraminidase* / genetics
  • Oseltamivir* / pharmacology
  • Oseltamivir* / therapeutic use
  • Schools

Substances

  • Oseltamivir
  • peramivir
  • Antiviral Agents
  • Acids, Carbocyclic
  • Cyclopentanes
  • Guanidines
  • Neuraminidase