title: Immunogenicity of two recombinant hepatitis B vaccines in older individuals.
abstract: OBJECTIVE
  Currently available hepatitis B vaccines are recombinant, yeast-derived preparations given in 10-micrograms or 20-micrograms doses. The optimum dose remains controversial. We sought to assess the relative immunogenicity of two hepatitis B vaccines, given in different doses, in older individuals.
  
  
  METHODS
  In a multicenter, double-blind, randomized clinical trial, a total of 460 healthy subjects between 39 and 70 years of age were screened and immunized with either Engerix-B 20 micrograms or Recombivax HB 10 micrograms in standard, intramuscular, 3-dose regimens. Of these, 397 subjects were eligible to continue vaccination. Immunogenicity was measured by determination of antibody to hepatitis B surface antigen (anti-HBs). Seroconversion and seroprotection rates, and geometric mean titers of anti-HBs were calculated at 1, 3, 6, and 8 months after the initial dose of vaccine.
  
  
  RESULTS
  Seroprotection rates for subjects receiving the 20-micrograms dose of vaccine were slightly, but not significantly, greater than for subjects receiving the 10-micrograms dose, at each time point. However, at 3 months, males receiving the higher dose had significantly higher seroprotection rates than males receiving the lower dose: 63% versus 37% (p < 0.001). At 8 months, geometric mean titers for the group receiving Engerix-B 20 micrograms were significantly greater than that for the group receiving Recombivax HB 10 micrograms: 840 mIU/mL versus 340 mIU/mL (p = 0.001).
  
  
  CONCLUSIONS
  Immunization with the 20-micrograms dose of recombinant hepatitis B virus vaccine appeared to result in more rapid development of seroprotective anti-HBs titers in older men and in higher titers of anti-HBs at the completion of vaccination when compared to the 10-micrograms dose. The latter data suggest that the 20-micrograms dose may result in a longer duration of seroprotective anti-HBs titers.
authors.affiliation: MetroWest Medical Center, Framingham, Massachusetts 01701.
authors.forename: T L
authors.initials: TL
authors.lastname: Treadwell
authors.forename: E B
authors.initials: EB
authors.lastname: Keeffe
authors.forename: J
authors.initials: J
authors.lastname: Lake
authors.forename: A
authors.initials: A
authors.lastname: Read
authors.forename: L S
authors.initials: LS
authors.lastname: Friedman
authors.forename: I S
authors.initials: IS
authors.lastname: Goldman
authors.forename: C D
authors.initials: CD
authors.lastname: Howell
authors.forename: M
authors.initials: M
authors.lastname: DeMedina
authors.forename: E R
authors.initials: ER
authors.lastname: Schiff
authors.forename: D M
authors.initials: DM
authors.lastname: Jensen
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D004306:Dose-Response Relationship, Immunologic; D004311:Double-Blind Method; D006510:Hepatitis B Antibodies / Q000097:blood; D017325:Hepatitis B Vaccines / Q000276:immunology*; D006515:Hepatitis B virus / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D014614:Vaccines, Synthetic / Q000276:immunology*
chemical_list: C075654:Engerix-B; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; C075655:Recombivax HB; D014614:Vaccines, Synthetic