title: Immunogenicity and estimation of antibody persistence following vaccination with an inactivated virosomal hepatitis A vaccine in adults: A 20-year follow-up study.
abstract: This was a 20-year follow-up study to assess long-term persistence of protective antibody levels against the hepatitis A virus (HAV) in healthy participants vaccinated with 2 doses of inactivated hepatitis A vaccine (Epaxal®) between 1992 and 1995.
  
  
  
  Blood samples for anti-HAV antibody concentrations were obtained during a follow-up visit 20years after vaccination and were analyzed in parallel with samples still available from previous visits using AxSYM® HAVAB 2.0 assay.
  
  
  
  Mean (SD) age of the participants was 44.71 (3.905) years at year 20 follow-up (N=95). Participants completing 0/12-month Epaxal® immunization regimen (N=94) had seroprotection rate of 100% (95% CI: 96.2, 100.0) with ⩾10mIU/mL seropositivity cut-off and 98.9% (95% CI: 94.2, 100.0) with ⩾20mIU/mL cut-off. With ⩾10mIU/mL cut-off, the estimated median duration of protection was 77.3years (95% CI: 71.8, 83.5) with 95% of the vaccinated participants predicted to be protected for at least 41.5years. At ⩾20mIU/mL cut-off, the estimated median duration of protection was 64.8years (95% CI: 60.1, 68.4) with 95% of the vaccinated participants predicted to be protected for at least 33years. Anti-HAV antibody geometric mean concentrations were higher in women (277.9; 95% CI: 217.7, 354.7) than in men (167.7; 95% CI: 125.2, 224.6).
  
  
  
  The data from this 20-year follow-up study confirm previous observations that two doses of Epaxal® provide protection against hepatitis A infection for at least 30years in over 95% of healthy participants.
authors.affiliation: Division of Tropical and Humanitarian Medicine, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Francois
authors.initials: F
authors.lastname: Chappuis
authors.affiliation: Division of Tropical and Humanitarian Medicine, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Farinelli
authors.affiliation: Janssen Infectious Diseases & Vaccines, Janssen Pharmaceutica NV, Belgium.
authors.forename: Henri
authors.initials: H
authors.lastname: Deckx
authors.affiliation: Janssen Vaccines AG, Bern, Switzerland. Electronic address: msarneck@its.jnj.com.
authors.forename: Michal
authors.initials: M
authors.lastname: Sarnecki
authors.affiliation: Janssen Research and Development, Raritan, USA.
authors.forename: Oscar
authors.initials: O
authors.lastname: Go
authors.affiliation: Janssen Vaccines AG, Bern, Switzerland.
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Salzgeber
authors.affiliation: Janssen Infectious Diseases and Vaccines, Leiden, The Netherlands.
authors.forename: Coby
authors.initials: C
authors.lastname: Stals
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D064368:Healthy Volunteers; D035922:Hepatitis A Antibodies / Q000097:blood*; D022362:Hepatitis A Vaccines / Q000008:administration & dosage / Q000276:immunology*; D030041:Hepatitis A virus / Q000276:immunology*; D006801:Humans; D056724:Immunity, Humoral; D007115:Immunization Schedule; D008297:Male; D011446:Prospective Studies; D013997:Time Factors; D022701:Virosomes / Q000276:immunology*; D055815:Young Adult
chemical_list: D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D022701:Virosomes; C530970:epaxal berna
keywords: Anti-HAV antibody; Duration; Epaxal®; Hepatitis A vaccine; Seroprotection