Comparative immunogenicity of hepatitis B vaccine with different dosages and schedules in healthy young adults in China.

OBJECTIVES: To compare immunogenicity of hepatitis B vaccine between the standard 3-dose (20 µg) and 2-dose with higher-dosage (60 µg) regimens in healthy young adults and evaluate the safety profile. METHODS: A randomized, parallel-group clinical trial was conducted among healthy young adults aged 18-25 years. Subjects were randomly assigned to three groups. One group was administered hepatitis B vaccine with the standard regimen of 0-1-6 month (20 µg) and other groups were immunized with regimens of 0-1 or 0-2 month (60 µg) respectively. Serum samples were collected at 1 month after a series vaccination and 12 months after the first-dose inoculation for anti-HBs antibody measurement with a Chemiluminescent Microparticle ImmunoAssay (CMIA). RESULTS: The seroprotection rates in 20 µg (0-1-6 month), 60 µg (0-1 month) and 60 µg (0-2 month) groups were 100, 93.64 and 99.19% at month 7/2/3, and 100, 96.04 and 95.90% at month 12, respectively. There were no significant differences among three vaccine groups (p>0.05). The geometric mean concentration (GMC) of anti-HBs was significantly higher in 20 µg (0-1-6 month) group than that in 60 µg (0-1 month) group at month 7/2 (1847.99 vs. 839.27 mIU/ml, p=0.004), but was similar to that in 60µg (0-2 month) group at month 7/3 (1847.99 vs. 1244.80 mIU/ml, p=0.138). At month 12, the GMC in 20 µg (0-1-6 month) group was significantly higher than those of other groups (1456.63 vs. 256.30, 235.15 mIU/ml, respectively, p<0.001). The total incidence of injection-site or systemic adverse reactions was <3%. CONCLUSIONS: A 2-dose with higher-dosage hepatitis B vaccine regimens are comparable to the standard 3-dose regimen in terms of immunogenicity except a relatively rapid decline in GMC levels which are associated with the longevity of protection. All formulations of hepatitis B vaccine were well tolerated. CLINICALTRIALS.GOV IDENTIfiER: NCT02203357.