title: Five years follow-up following two or three doses of a hepatitis B vaccine in adolescents aged 11-15 years: a randomised controlled study.
abstract: BACKGROUND
  The standard three-dose schedule of hepatitis B vaccines is frequently not completed, especially in adolescents. A primary study has confirmed the equivalence of a two-dose schedule of an Adult formulation of hepatitis B vaccine [Group HBV_2D] to a three-dose schedule of a Paediatric formulation in adolescents (11-15 years) [Group HBV_3D]. This follow-up study evaluated the five year persistence of antibody response and immune memory against the hepatitis B surface (anti-HBs) antigens five years after completion of primary vaccination.
  
  
  METHODS
  A total of 234 subjects returned at the Year 5 time point, of which 144 subjects received a challenge dose of hepatitis B vaccine. Blood samples were collected yearly and pre- and post-challenge dose to assess anti-HBs antibody concentrations.
  
  
  RESULTS
  At the end of five years, 79.5% (95% confidence interval [CI]: 71.7 - 86.1) and 91.4% (95% CI: 82.3 - 96.8) of subjects who received the two-dose and three-dose schedules, respectively had anti-HBs antibody concentrations ≥ 10 mIU/mL. Post-challenge dose, all subjects had anti-HBs antibody concentration ≥ 10 mIU/mL and >94% subjects had anti-HBs antibody concentration ≥ 100 mIU/mL. All subjects mounted a rapid anamnestic response to the challenge dose. Overall, the challenge dose was well-tolerated.
  
  
  CONCLUSIONS
  The two-dose schedule of hepatitis B vaccine confers long-term immunogenicity and shows evidence of immune memory for at least five years following vaccination.
  
  
  BACKGROUND
  Clinical Trials NCT00343915, NCT00524576.
authors.affiliation: Faculty of Medicine, Vaccine & Infectious Disease Institute (WHO Collaborating Centre), Centre for Evaluation of Vaccination, Antwerpen, Belgium. pierre.vandamme@ua.ac.be
authors.forename: Pierre
authors.initials: P
authors.lastname: Van Damme
authors.forename: Anna
authors.initials: A
authors.lastname: Moiseeva
authors.forename: Igor
authors.initials: I
authors.lastname: Marichev
authors.forename: Anne-Diane
authors.initials: AD
authors.lastname: Kervyn
authors.forename: Robert
authors.initials: R
authors.lastname: Booy
authors.forename: Sherine
authors.initials: S
authors.lastname: Kuriyakose
authors.forename: Andrew
authors.initials: A
authors.lastname: Brockway
authors.forename: Su-Peing
authors.initials: SP
authors.lastname: Ng
authors.forename: Maarten
authors.initials: M
authors.lastname: Leyssen
authors.forename: Jeanne-Marie
authors.initials: JM
authors.lastname: Jacquet
mesh_terms: D000293:Adolescent; D001315:Australia; D001530:Belgium; D005260:Female; D005500:Follow-Up Studies; D006509:Hepatitis B / Q000517:prevention & control; D006510:Hepatitis B Antibodies / Q000097:blood; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000276:immunology; D006801:Humans; D007115:Immunization Schedule; D007156:Immunologic Memory; D008297:Male; D014455:Ukraine; D014611:Vaccination / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines