title: Debate on annual influenza vaccination in healthcare workers for the same subtype under the vaccine shortage.
abstract: BACKGROUND
  Influenza vaccination is the primary method for preventing influenza and its severe complications. Healthcare workers (HCWs) are one of the priority groups for the influenza vaccination.
  
  
  OBJECTIVE
  To determine whether healthy HCWs, who were vaccinated with the same subtype for the two previous years, could be given less priority for influenza immunization under the vaccine shortage.
  
  
  METHODS
  We measured hemagglutination-inhibition antibody titers from sequential serum samples in 50 pre-immune subjects and 50 age-matched vaccine-naive subjects: immediately prior to the administration of the vaccine, 4-6 weeks, and 6 months after the vaccination.
  
  
  RESULTS
  Prevaccination titers were maintained above protective level and high protection rates were observed for all three strains in pre-immune subjects: A/H1N1, A/H3N2, and B strains. As for the sequential changes, the protection rates for all three strains still remained above 70% until 6 months following the vaccination.
  
  
  CONCLUSIONS
  Skipping influenza vaccination for a year could be considered in healthy pre-immune HCWs under the epidemic of the same subtype as two previous years.
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Korea University, Seoul, Republic of Korea.
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Song
authors.forename: Seok Hoon
authors.initials: SH
authors.lastname: Ha
authors.forename: Sae Yoon
authors.initials: SY
authors.lastname: Kee
authors.forename: Hye Won
authors.initials: HW
authors.lastname: Jeong
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Cheong
authors.forename: Woo Joo
authors.initials: WJ
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood* / Q000276:immunology; D006282:Health Personnel; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D053122:Influenza A Virus, H3N2 Subtype / Q000276:immunology*; D009981:Influenza B virus / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology* / Q000600:supply & distribution; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines