title: Persistence of immunity in healthy adults aged ≥ 50 years primed with a hepatitis B vaccine 3 years previously.
abstract: Hepatitis B vaccines do not generate protective immune responses in older adults as effectively as they do in children and young adults. Improved formulations of existing vaccines may have the potential to improve this. This study investigated the persistence of serum antibodies against hepatitis B surface antigens (anti-HBs) 3.1-3.5 years following primary vaccination with 3 doses of HBvaxPRO® or Engerix B™ in healthy adults aged ≥ 50 years who were further challenged with 1 dose of recombinant hepatitis B antigen. This was an open-label extension study. Individuals (N = 204) with a mean (standard deviation) age at enrollment of 63.7 (7.0) years receiving HBvaxPRO® or Engerix B™ in a randomized, double-blind primary study were challenged with 1 dose of HBvaxPRO® (10 μg). Anti-HBs were measured pre- and 30 days post-challenge. 45.5% (34.8, 56.4 [95% CI]) of individuals who received HBvaxPRO® in the per protocol set (PPS) had anti-HBs titers ≥ 10 mIU/mL pre-challenge and 85.2% (76.1, 91.9) 1-month post-challenge. In those who received Engerix B™ in the primary vaccination series, the results were 58.8% (48.6, 68.5) and 88.3% (80.5, 93.8), respectively. The challenge dose of HBvaxPRO® was generally well tolerated. Subjects aged ≥ 50 years receiving a challenge dose of HBvaxPRO® demonstrated immune memory against hepatitis B 3 years after a 3-dose primary. The safety profile of this challenge dose of HBvaxPRO® was consistent with the well-established safety profile of the vaccine HBvaxPRO®.
authors.affiliation: a Sea Road Surgery; Bexhill-on-Sea , East Sussex , UK.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Sharma
authors.forename: Clas
authors.initials: C
authors.lastname: Ahlm
authors.forename: Lars
authors.initials: L
authors.lastname: Ostergaard
authors.forename: Anthony
authors.initials: A
authors.lastname: Dowell
authors.forename: Clément
authors.initials: C
authors.lastname: Tran
authors.forename: Stéphane
authors.initials: S
authors.lastname: Thomas
authors.forename: Cécile
authors.initials: C
authors.lastname: Eymin
mesh_terms: D000328:Adult; D004311:Double-Blind Method; D005260:Female; D006509:Hepatitis B / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000097:blood*; D006514:Hepatitis B Surface Antigens / Q000276:immunology*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D006801:Humans; D007117:Immunization, Secondary; D007156:Immunologic Memory; D008297:Male; D008875:Middle Aged; D013997:Time Factors
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D017325:Hepatitis B Vaccines
keywords: AE, adverse event; CI, confidence interval; GMT, geometric mean titer; HBsAg, hepatitis B surface antigen; PPS, per protocol set; SAE, serious adverse event; SAS, safety analysis set; SD, standard deviation; SPR, seroprotection rate; adult; anti-HBs, antibody to HBsAg; hepatitis B; immunity; persistence; vaccination