Safety and immunogenicity of a modified process hepatitis B vaccine in healthy adults ≥50 years

Abstract

Background: Generating protective immune responses in older adults (particularly ≥65 y) remains challenging for vaccines in general. This study examined the immune response engendered in older adults by REC OMBIVAX HBTM manufactured using a modified adjuvant (modified-process hepatitis B vaccine; mpHBV), REC OMBIVAX-HBTM and ENGERIX-BTM. Results: For subjects ≥50 y, seroprotection rates (SP R, anti-HBs titer ≥10 mIU/mL) were 75.7% (95% CI: 68.0, 82.2) for mpHBV, 68.0% (95% CI: 59.8, 75.5) for REC OMBIVAX HBTM, and 84.0% (95% CI: 77.0, 89.6) for ENGERIX-BTM. For subjects 50-64 y, SP Rs were 82.1% (95% CI: 73.8, 88.7) for mpHBV, 77.4% (95% CI: 68.7, 84.7) for REC OMBIVAX-HBTM, and 88.5% (95% CI: 81.1, 93.7) for ENGERIX-BTM. For subjects ≥65 y, SP Rs were 57.5% (95% CI: 40.9,73.0) for mpHBV, 34.4% (95% CI: 18.6, 53.2) for REC OMBIVAX-HBTM, and 67.7% (95% CI: 48.6, 83.3) for ENGERIX-BTM. There were 6 non-vaccine related serious adverse events reported. Methods: Randomized, double-blind, multicenter study enrolled healthy, seronegative subjects (N = 538) to receive mpHBV (10 ìg hepatitis B surface antigen [HBsAg]), REC OMBIVAX-HBTM (10 μg HBsAg), or ENGERIX-BTM (20 μg HBsAg) at Day 1, Month 1 and Month 6. Prespecified analysis of subpopulations 50-64 y and ≥65 y was conducted. Serum antibody to HBsAg (anti-HBs) was measured Predose 1 and 1 mo Postdose 3. Conclusions: The majority of subjects ≥50 y old achieved seroprotection. The sub-population ≥65 y had lower vaccination responses than the 50-64 y sub-population. For subjects ≥65 y, mpHBV and ENGERIX-BTM groups achieved higher seroprotection rates than the REC OMBIVAX-HB group. The safety profile of mpHBV was consistent with the other groups. © 2011 Landes Bioscience.