Comparison of immunogenicity between hepatitis B vaccines with different dosages and schedules among healthy young adults in China: A 2-year follow-up study.

Immunogenicity of hepatitis B vaccine between 20 µg with 3-dose schedule and 60 µg with 2-dose regimens was compared 2 years after primary immunization. A total of 353 healthy adults aged 18-25 years were enrolled in the study and randomly assigned (1: 1: 1) into 3 vaccine groups: A (20 µg, 0-1-6 month), B (60 µg, 0-1 month) and C (60 µg, 0-2 month). Serum samples were collected at 1 month after a series vaccination and 12 months, 24 months after the first-dose. The GMC level of anti-HBs antibody was measured using Chemiluminescent Microparticle ImmunoAssay (CMIA). There were 59, 45 and 55 vaccinees available to follow-up with 2 year later in vaccine groups A, B and C, respectively. No significant differences existed in sex ratio, age and body mass index (BMI) among vaccinees at month 24 and the corresponding participants at baseline in each group (P > 0.05). The seroprotection rates in group A, B and C were 98.31%, 88.37% and 85.19%, respectively (P = 0.014), reflecting the fact that the rate of group A was significantly higher than that in group C (P = 0.026). Also, the GMC level of anti-HBs antibody in group A was significantly higher than those of other two groups (427.46 mIU/ml vs. 89.74 mIU/ml, 89.80 mIU/ml, respectively; all P < 0.01). This data suggested that the standard 20 µg (0-1-6 month) regimen of hepatitis B vaccine should be recommended as a priority on the premise of complete compliance in adults.

Long-term persistence in protection and response to a hepatitis B vaccine booster among adolescents immunized in infancy in the western region of China.

OBJECTIVES: To evaluate the persistence of protection from hepatitis B (HB) vaccination among adolescents immunized with a primary series of HB vaccine as infants, and the immune response to booster doses. METHODS: Healthy adolescents aged 15-17 y vaccinated with HB vaccine only at birth were enrolled. Baseline serum hepatitis B surface antigen (HBsAg), antibody against hepatitis B surface antigen (anti-HBs) and antibody against hepatitis B core antigen (anti-HBc) were detected by Enzyme-Linked Immunosorbent Assay (ELISA) and anti-HBs level was measured using Chemiluminescent Microparticle Immunoassay (CMIA). The rate of HBV infection was calculated. The seroprotection rate of anti-HBs (≥ 10 mIU/ml) and GMC level were used to evaluate the persistence of immunity from HB vaccination. Those with anti-HBs < 10 mIU/ml were immunized with booster doses of HB vaccine and the anamnestic response was assessed. RESULTS: Of 180 adolescents who received a primary series of HB vaccinations as infants, 3 (1.7%) had HBV infection and 74 (41.1%) had anti-HBs ≥ 10 mIU/ml with a GMC of 145.11 mIU/ml. The remaining 103 (57.2%) with anti-HBs < 10 mIU/ml received a booster dose of 20 µg HB vaccine and achieved the seroprotection rate of 84% (84/100) and a GMC of 875.19 mIU/ml at one month post-booster. An additional dose of 60 µg HB vaccine was administered to the 16 adolescents with anti-HBs < 10 mIU/ml after the first booster. All of them obtained anti-HBs seroprotection with a GMC of 271.02 mIU/ml at 1.5 months after an additional dose. CONCLUSIONS: Vaccine-induced immunity persisted for up to 15-17 y in 89.3% (158/177) of participants after a primary HB vaccination in infancy. Administering a booster dose of 20µg HB vaccine elicited an anamnestic immune responses in the majority of individuals with baseline anti-HBs <10 mIU/ml.

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.