Immunogenicity of two recombinant hepatitis B vaccines in older individuals.
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.
Treadwell
T L
TL
MetroWest Medical Center, Framingham, Massachusetts 01701.
Keeffe
E B
EB
Lake
J
J
Read
A
A
Friedman
L S
LS
Goldman
I S
IS
Howell
C D
CD
DeMedina
M
M
Schiff
E R
ER
Jensen
D M
DM
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*
C075654:Engerix-B; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; C075655:Recombivax HB; D014614:Vaccines, Synthetic