A 2-DOSE HEPATITIS-B VACCINE REGIMEN - PROOF OF PRIMING AND MEMORY RESPONSES IN YOUNG-ADULTS

This study shows that two doses of a recombinant hepatitis B vaccine ( 10 mu g or 20 mu g of HBsAg per dose), administered 6 months apart to young, healthy adults, can induce an antibody (anti-HBs) response simi lar to that expected with the standard three-dose regimen of this vacc ine given at intervals of 0, 1 and 6 months. While only 46-67% of vacc inees displayed a protective anti-HBs titer of greater than or equal t o 10 mIU ml(-1) prior to the receipt of the second dose at 6 months, v irtually all were primed as 97-99% of the subjects developed such a ti ter when tested a month after the second dose. Among vaccinees given 1 0 or 20 mu g doses, respectively, the secondary rise in antibody follo wing the second dose yielded geometric mean titers (GMTs) of 1103 and 2538 mIU ml(-1), respectively. The study further demonstrated that a t wo-dose regimen of vaccination induced strong immunologic memory for H BsAg, as a booster dose of vaccine given 2 years later resulted in a r apid and vigorous anamnestic antibody response. (C) 1998 Elsevier Scie nce Ltd. All rights reserved.