Recombinant hepatitis B vaccine(Hualan Biological Bacterin Co., Ltd.)

To compare the efficacy of double dose (20 µg) with standard dose (10 µg) of hepatitis B vaccine in HIV-infected children.

Unvaccinated HIV-infected children were randomized to receive 3 doses of double dose (N=27) or standard dose (N=28) of recombinant Hepatitis B vaccine. Anti-HBs antibody titres were measured 3 mo after the last dose. An antibody titre ≥10 mIU/mL 12 weaks after the third dose was considered as serporotection.

Seroprotection was achieved by 17 (60.7%) children in standard dose group against 20 (74%) in the double dose group [RR (95%CI) 0.8 (0.17-1.7); P=0.29]. CD4 count < 500 cells/mm3 was significantly associated with lower rates of seroprotection.

Double dose of hepatitis B vaccine does not seem to provide any advantage when compared to standard dose in HIV-infected children.

The current 3-dose regimen of hepatitis B vaccination for infants requiring over 6 mo period may pose the poor rate of compliance and later protection from hepatitis B virus (HBV) infection. This preclinical study is to investigate the feasibility of reducing the number of doses of hepatitis B (HB) vaccine.

Eight groups of guinea pigs immunized with two doses of HP-HB vaccines at either 0 and 4 weeks or 0 and 8 weeks elicited geometric titers (GMT) of anti-HBs similar to that of four groups immunized with three doses of controls. The overall GMT of anti-HBs were not significantly different between the E- and C-groups (p>0.05) of monkeys. Specifically, the anti-HBs titers in the C-group reached the peak of 24857 (938.3-104585) mIU/mL one week after the 3rd dose, which were statistically higher than those of the E-group. However, they were reduced to comparable levels of anti-HBs in the E-group during weeks 9-12, suggesting comparable immune response of both vaccination regimens.

Twelve groups of guinea pigs (four animals in each group) were immunized with 2 experimental recombinant yeast Hansenula Polymorpha derived HB vaccines (HP-HB vaccine) and 2 commercial recombinant yeast Saccharomyces Cerevisiae vaccines (Temrevac-HB) as controls at 0, 4 and 8 weeks, 0 and 4 weeks, and 0 and 8 weeks respectively. Each guinea pig received 2 µg vaccine. Twelve Cynomolgus monkeys were randomly divided into two groups (six animals in each group). Animals in the experimental group (E-group) were injected with two doses of pilot produced 20 µg HP-HB vaccine. Animals in the control group (C-Group) were immunized with three doses of 10 µg Temrevac-HB. Both vaccines were administered at an interval of 3 weeks for monkeys.

The 2-dose regimen of the HP-HB vaccine has comparable HBV immune responses as the 3-dose regimen of Temrevac-HB vaccine in Cynomolgus monkeys.