title: Low level of immunity against hepatitis A among Korean adolescents: vaccination rate and related factors.
abstract: BACKGROUND
  We evaluated the current vaccination rate and immunity in the Korean adolescent population and analyzed their parents' attitudes toward hepatitis A virus (HAV) vaccination.
  
  
  METHODS
  Between March and April 2011, sera were collected for immunoglobulin (Ig) G anti-HAV testing from students in their first year of high school from 12 different high schools located in southwestern Seoul. Simultaneously, questionnaires were given to the parents of the students to evaluate factors related to HAV vaccination, including demographics, HAV vaccination status, reason for getting the vaccination, and awareness regarding HAV.
  
  
  RESULTS
  Sera from 2,879 subjects and questionnaires from their parents were collected. The HAV vaccination rate among adolescents aged between 14 and 17 years was 18.9%, and the seroprevalence was 15.4%. Among subjects who reported receiving the HAV vaccination, the IgG anti-HAV seropositivity rate was only 42.2%. For subjects who were not vaccinated, the IgG anti-HAV seropositivity rate was 9.1%. The most significant reason for receiving the vaccination was recommendation from health care providers; the most important source of information regarding the vaccination was public health organizations.
  
  
  CONCLUSIONS
  HAV vaccination rate and anti-HAV seroprevalence in Korean adolescents was low; the seropositivity rate in the vaccinated group was lower than expected. Actively recommending HAV vaccination in this group is required, and routine, nationwide, government-sponsored vaccination of adolescents against HAV should be considered.
authors.affiliation: Department of Epidemiology, Korea University Graduate School of Public Health, Seoul, Korea.
authors.forename: Jung Yeon
authors.initials: JY
authors.lastname: Heo
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Song
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Noh
authors.forename: Yu Bin
authors.initials: YB
authors.lastname: Seo
authors.forename: In Sun
authors.initials: IS
authors.lastname: Kim
authors.forename: Won Suk
authors.initials: WS
authors.lastname: Choi
authors.forename: Woo Joo
authors.initials: WJ
authors.lastname: Kim
authors.forename: Gum Joo
authors.initials: GJ
authors.lastname: Cho
authors.forename: Taik Gun
authors.initials: TG
authors.lastname: Hwang
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Cheong
mesh_terms: D000293:Adolescent; D005260:Female; D006506:Hepatitis A / Q000517:prevention & control*; D035922:Hepatitis A Antibodies / Q000097:blood*; D022362:Hepatitis A Vaccines / Q000008:administration & dosage*; D006801:Humans; D007118:Immunoassay; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D056910:Republic of Korea; D012574:Schools; D013334:Students; D011795:Surveys and Questionnaires; D014611:Vaccination
chemical_list: D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D007074:Immunoglobulin G
keywords: Epidemiology; Hepatitis A virus; Seroprevalence