Comparison of the effect of two different doses of recombinant hepatitis B vaccine on immunogenicity in healthy adults.

The aim of this study was to evaluate the one-month immune response to 2 different doses (10 and 20 mu g) of recombinant hepatitis B vaccine in adults aged 20-46 y. Subjects who were negative for hepatitis B surface antigen (HBsAg), hepatitis B antibody (anti-HBs), and hepatitis B core antibody (anti-HBc) were recruited. The participants were divided into 2 groups: group I received 3 doses of 10 mu g hepatitis B vaccine at 0, 1 and 3 months, and group II received 3 doses of 20 mu g at the same time points. The anti-HBs levels were measured one month after the third vaccination. Among 739 subjects, 62 (9.70%) were positive for HBsAg, and 317 subjects were eligible. The anti-HBs seroprotection rates (anti-HBs >= 10 mIU/mL was considered to indicate seroprotection) after the third vaccination were 88.05% and 94.06% in group I and group II respectively, and the geometric mean titers were 91.69 and 290.23 mIU/mL respectively. The difference in the seroprotection rate was not significant (chi(2) = 2.566, P > 0.05), but the GMT after the third dose was significantly lower for group I than for group II (F = 20.587, P < 0.05). Better responses were observed in young adults, especially in group I. In group I, the seroprotection rate and GMT were significantly higher in the 20-35 y group than in the 36-46 y group (P < 0.05); there was no significant difference compared to group II (P > 0.05). The hepatitis B vaccine has good immunological effect; the 20 mu g dose can be used in adults aged 20-46 y and the 10 mu g dose can be used in subjects aged 20-35 years, and it should be tested on a larger number of subjects before recommending it for adult routine vaccination.