Rapid seroprotection against hepatitis B following the first dose of a Pre-S1/Pre-S2/S vaccine.

Abstract Background/Aims : Will immunization with an experimental Pre-S 1 /Pre-S 2 /S hepatitis B vaccine (Bio-Hep-B ™ ) induce faster seroprotection using fewer doses as compared with a yeast derived S vaccine (Engerix B ® ). Methods : Healthy volunteers, n =36, mean age 23 y, randomized to receive 2 or 3 doses of both vaccines given months 0 and 6, or 0, 1 and 6. Results : Following primary immunization, seroprotection occurred in 6, 39, 53 and 60% in the Bio-Hep-B ™ group at weeks 1, 2, 3 and 4, compared with 0, 12, 18 and 12.5% in the Engerix-B ® vaccinees, respectively. Six months following injection of the first dose, seroprotection was 70 and 25% in Pre-S/S and S vaccinees respectively. Area under the curve in vaccinees of Bio-Hep-B ™ ; versus Engerix-B ® showed mean anti-HBs level of 365±166 and 85±48 mIU/ml×day respectively ( P =0.012). At month 7, 100% seroprotection was achieved in both groups while anti-HBs rose from 81 to 28 800 mIU/ml and from 12 to 923 mIU/ml in recipients of Bio-Hep-B ™ and Engerix-B ® respectively ( P Conclusions : Bio-Hep-B ™ induces rapid seroprotection against hepatitis B in 60–70% of vaccinees, within 4–24 weeks after the first dose. Two instead of the conventional three doses of the Pre-S/S vaccine may be sufficient to induce adequate seroprotection.