Vaccination against hepatitis B: comparison of three different vaccination schedules.

Three different hepatitis B vaccination schedules employing injections at months 0, 1, 2, and 12, at months 0, 1, and 6, or at months 0, 1, and 12 were compared in 89 healthy young adults. Concentrations of antibodies to hepatitis B surface antigen (anti-HBs) after the third injection were dependent on the interval between the second and the third dose; geometric mean titers (GMTs) in the three groups were 53 IU/l, 5,846 IU/l, and 19,912 IU/l, respectively, when the third dose was given at month 2, 6, or 12. Whereas the anti-HBs responses to the third dose at month 6 or 12 were typical booster reactions, the kinetics after a third dose given at month 2 resembled those after only two doses but on a significantly higher level. A fourth dose given at month 12 to the individuals vaccinated at months 0, 1, and 2 led to a prompt anti-HBs response similar in height to the response in those vaccinated at months 0, 1, and 12. Thus, for achieving a high anti-HBs concentration guaranteeing its long-lasting persistence, vaccination at months 0, 1, and 12 seems to be preferable to vaccination at months 0, 1, and 6. For individuals at high risk of hepatitis B infection, vaccination at months 0, 1, 2, and 12 might be considered for obtaining an optimal early seroconversion as well as long-term protection.