Rapid seroprotection against hepatitis B following the first dose of a Pre-S-1/Pre-S-2/S vaccine

Backgrond/Aims: Will immunization with an experimental Pre-S-1/Pre-S2/S hep atitis B vaccine (Bio-Hep-B(TM)) induce faster seroprotection using fewer d oses as compared with a yeast derived S vaccine (Engerix B(R)). 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-HepB(TM) group at weeks 1, 2, 3 and 4, compared with 0, 12, 18 and 12.5% in the Engerix-B(R) vaccinees, respectively. Six months following injection of the first dose, seroprotection was 70 and 25% in Pr e-S/S and S vaccinees respectively. Area under the curve in vaccinees of Bi o-Hep-B(TM); versus Engerix-B(R) showed mean anti-HBs level of 365 +/- 166 and 85 +/- 48 mIU/ml x day respectively (P = 0.012). At month 7, 100% serop rotection 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(TM) and Engeri x-B(R) respectively (P < 0.025). Conclusions: Bio-Hep-B(TM) induces rapid seroprotection against hepatitis B in 60-70% of vaccinees, within 4-24 weeks after the first dose. Two instea d of the conventional three doses of the Pre-S/S vaccine may be sufficient to induce adequate seroprotection. (C) 2001 European Association for the Study of the Liver. Published by Else vier Science B.V. All rights reserved.