Is a low dose of hepatitis B vaccine enough for a rapid vaccination scheme?

AIM: To determine whether or not a low dose of HB vaccine can be effectively used in the rapid vaccination.METHODS: Rapid vaccination (0, 1, 2 months) with low dose (5 μg) or routine dose (10 μg) HB vaccine was studied in 250 subjects (130 school children and 120 university students). Serum from all the participants was tested for HBsAg, anti-HBs and anti-HBc at 1, 3 and 7 months after the first dose of vaccination and all subjects were serum HBV marks negative before the vaccination. Non-responders to a complete initial vaccination from university students were given an additional vaccination with 10 μg of HB vaccine and their serum anti-HBs was tested again one month later.RESULTS: One month after the third dose of vaccination (third month) sero-conversion rates and geometric mean titer (GMTs) were significantly (P＜0.01) higher in the routine dose (resp. 89 % and 106.8) than in the low dose group (resp. 72 % and 59.5). Sero-conversion rates and GMTs were maintained stable for another 4 months in both groups.After an additional vaccination to non-responders with 10 μg HB vaccine, 17/23 subjects (13/15 from those vaccinated with 5 μg vaccine and 4/8 from those vaccinated with 10 μg vaccine) became anti-HBs positive, yielding similar seroconversion rates for both dose groups.CONCLUSION: Higher sero-conversion rates and GMTs were reached in those vaccinated with 10 μg HB vaccine than in those vaccinated with 5 μg HB vaccine after a comp^te vaccination with a 0, 1, 2 month scheme. But the subjects vaccinated with 5 μg vaccine can also reach the similar sero-conversion rate after an additional vaccination.

Can HB vaccine yield a booster effect on individuals with positive serum anti-HBs and anti-HBc markers?

AIM:To evaluate if HB vaccination can yield a booster effect on the anti-HBs level of those naturally acquired HBV positive markers.METHODS:Sera were collected from 1399 newly enrolled university students aged between 18-20 years at the entrance medical examination in 2001.Forty-four students (28 males and 16 females) with positive serum anti-HBs and anti-HBc markers served as an observation group and another 44 students (24 males and 20 females) without any HBV markers as the control. HB vaccination was given to all the students without positive serum HBsAg according to 0,1, 6 month regimen and the peripheral venous blood was sampled from those of both observation and control groups for anti-HBs detection one month after the second and third doses.Anti-HBs levels were measured by ELISA.RESULTS:The seroconversion rate of anti-HBs in the control group was 100% after the second dose,but the geometric mean titers (GMTs) were low.The tendency of serum anti-HBs changes after the 3^rd dose was completely different between the two groups.Although more than half of those with positive anti-HBs and anti-HBc showed a mild increase of anti-HBs levels after the 2na boosting dose (mean antiHBs level was 320:198 mIU),but the increase of serum anti-HBs titer was much smaller than that in the control group.The averages of their initial serum anti-HBs levels and the levels after the 2^nd and 3^rd doses were 198, 320 and 275 mIU respectively. All the subjects from the control group had an obvious increase in their serum anti-HBs levels which was nearly 4 times the baseline level (302:78 mIU).CONCLUSION: HB vaccination can not enhance anti-HBs levels in those with positive serum anti-HBs and anti-HBc markers.