Objective To explore efficacy of different doses of hepatitis B vaccine

and to provide scientific basis for prevention of hepatitis B.Method Of the freshman from 2007 to 2009 in Zhaoqing University

3 016 students who were detected with HBsAg-negative received vaccination against hepatitis B and the dose was 5 μg every time（once for the first month

the second month and the sixth month respectively）.The status of positive conversion of anti-HBs after one month

two months and twelve months of injection was investigated.Students with anti-HBs negative after one month of inoculation received full course of vaccination and the dose was 10 μg every time

and the status of positive conversion of anti-HBs after one month

two months and twelve months of inoculation was investigated and a comparative analysis was carried out.Results The positive rates of anti-HBs after one month

two months and twelve months of inoculation（5 μg every time） were 72.65%

62.17% and 53.88% respectively;as for students with anti-HBs negative

the positive rates of anti-HBs after one month

two months and twelve months of inoculation（10 μg every time） were 93.58%

91.27% and 89.58% respectively;as for the group receiving injection of 5 μg every time

the positive rate of anti-HBs decreased with time prolonging

and the difference was statistically significant（P<0.01）;when the positive rate of anti-HBs after twelve months of inoculation was lower than that after one month of inoculation the the group receiving injection of 10 μg every time had statistically significant difference（P<0.01）;the inoculation after one month and two months and the injection after two months and twelve months had no statistically significant differences（P>0.05）.Conclusion The efficacy of hepatitis B vaccine is good.After the inoculation of 5 μg every time with anti-HBs negative ischanged into 10 μg every time

the short-term and long-term efficacy is good.