title: Antibody persistence and immune memory in adults, 15 years after a three-dose schedule of a combined hepatitis A and B vaccine.
abstract: A combined hepatitis A and B vaccine is available since 1996. Two separate open-label primary studies evaluated the immunogenicity and safety of this hepatitis A and B vaccine (720 EI.U of HAV and 20 µg of HBsAg) in 306 healthy subjects aged 17-43 years who received three doses of the vaccine following a 0, 1, and 6 months schedule. These subjects were followed up annually for the next 15 years to evaluate long-term persistence of anti-HAV and anti-HBs antibodies. The subjects whose antibody concentrations fell below the cut-offs between Year 11 and Year 15 (anti-HAV: <15 mIU/ml; anti-HBs: <10 mIU/ml) were offered an additional dose of the appropriate monovalent hepatitis A and/or B vaccine. In subjects who received the additional vaccine dose, a blood sample was collected 1 month after vaccination. At the Year 15 time point, all subjects in Study A and Study B were seropositive for anti-HAV antibodies and 89.3% and 92.9% of subjects in the respective studies had anti-HBs antibody concentrations ≥10 mIU/ml. Four subjects (two in each study) received an additional dose of monovalent hepatitis B vaccine and mounted anamnestic responses to vaccination. No vaccine-related serious adverse events were reported. This study confirms the long-term immunogenicity of the three-dose regimen of the combined hepatitis A and B vaccine, as eliciting long-term persistence of antibodies and immune memory against hepatitis A and B for up to at least 15 years after a primary vaccination.
authors: Vaccine & Infectious Disease Institute, Centre for the Evaluation of Vaccination (WHO Collaborating Centre) Campus Drie Eiken, Universiteitsplein 1, Antwerpen, Belgium. pierre.vandamme@ua.ac.be
authors: P
authors: P
authors: Van Damme
authors: G
authors: G
authors: Leroux-Roels
authors: P
authors: P
authors: Crasta
authors: M
authors: M
authors: Messier
authors: J-M
authors: JM
authors: Jacquet
authors: K
authors: K
authors: Van Herck
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D035922:Hepatitis A Antibodies / Q000097:blood*; D022362:Hepatitis A Vaccines / Q000008:administration & dosage / Q000276:immunology*; D006510:Hepatitis B Antibodies / Q000097:blood*; D006801:Humans; D007117:Immunization, Secondary / Q000379:methods; D007156:Immunologic Memory; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D014611:Vaccination / Q000379:methods; D055815:Young Adult
chemical_list: D035922:Hepatitis A Antibodies; D022362:Hepatitis A Vaccines; D006510:Hepatitis B Antibodies