A two-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 similar to that expected with the standard three-dose regimen of this vaccine given at intervals of 0, 1 and 6 months. While only 46-67% of vaccinees displayed a protective anti-HBs titer of greater than or equal to 10 mIU ml(-1) prior to the receipt of the second dose at 6 months, virtually all were primed as 97-99% of the subjects developed such a titer when tested a month after the second dose. Among vaccinees given 10 or 20 mu g doses, respectively, the secondary rise in antibody following the second dose yielded geometric mean titers (GMTs) of 1103 and 2538 mIU ml(-1), respectively. The study further demonstrated that a two-dose regimen of vaccination induced strong immunologic memory for HBsAg, as a booster dose of vaccine given 2 years later resulted in a rapid and vigorous anamnestic antibody response. (C) 1998 Elsevier Science Ltd. All rights reserved.