Antibodies Against the Current Influenza A(H1N1) Vaccine Strain Do Not Protect Some Individuals From Infection With Contemporary Circulating Influenza A(H1N1) Virus Strains

J Infect Dis. 2016 Dec 15;214(12):1947-1951. doi: 10.1093/infdis/jiw479. Epub 2016 Oct 7.


During the 2013-2014 influenza season, nearly all circulating 2009 pandemic influenza A(H1N1) virus (A[H1N1]pdm09) strains possessed an antigenically important mutation in hemagglutinin (K166Q). Here, we performed hemagglutination-inhibition (HAI) assays, using sera collected from 382 individuals prior to the 2013-2014 season, and we determined whether HAI titers were associated with protection from A(H1N1)pdm09 infection. Protection was associated with HAI titers against an A(H1N1)pdm09 strain possessing the K166Q mutation but not with HAI titers against the current A(H1N1)pdm09 vaccine strain, which lacks this mutation. These data indicate that contemporary A(H1N1)pdm09 strains are antigenically distinct from the current A(H1N1)pdm09 vaccine strain.

Keywords: antigenic drift; correlates of protection; hemagglutinin; household cohort; influenza; influenza vaccine; pandemic H1N1; serum antibody.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Antibodies, Viral / blood*
  • Cross Protection
  • Female
  • Hemagglutination Inhibition Tests
  • Humans
  • Influenza A Virus, H1N1 Subtype / immunology*
  • Influenza Vaccines / administration & dosage
  • Influenza Vaccines / immunology*
  • Influenza, Human / immunology
  • Influenza, Human / prevention & control*
  • Influenza, Human / virology*
  • Male
  • Middle Aged
  • Young Adult


  • Antibodies, Viral
  • Influenza Vaccines