Objective To evaluate the long-term protective effectiveness of plasma-derived hepatitis B vaccine on neonates,and to provide scientific basis for perfecting the hepatitis B immunization strategy.
Methods Using a three tier sampling strategy,2 692 adolescents born in 1986-1996 in 6 neighborhoods of 2 districts,who were vaccinated with 3 dosages of plasma-derived hepatitis B vaccines after birth,were selected as subjects of the study.They were divided into 11 groups according to the calendar year of vaccinating time.Questionnaires were made and blood samples were collected to test hepatitis B surface antibody (anti-HBs),hepatitis B surface antigen (HbsAg) and hepatitis B core antibody (anti-HBc).
Results The average positive rate of HBsAg was 1.75% and did not show an uptrend with the increasing of age.The average positive rate of anti-HBc was 3.64%,and showed a rising tendency along with the increasing of age.The average positive rate of anti-HBs was 40.16%,and that of the adolescents below 18 years old decreased along with the increasing of age;however,that of the adolescents above 19 increased along with the increasing of age.The negative rate of anti-HBs of the 15-19-year olds was the highest (66.80%).The multivariate logistic regression showed that being infected with hepatitis B e antigen (HBeAg) during pregnancy,family members of HBsAg carrier,gender,and age were the risk factors of hepatitis B virus infection of adolescents.
Conclusion Plasma-derived hepatitis B vaccine has persistent protective effects.It is suggested that the follow-up of people above 15 years old should be strengthened,and people with negative anti-HBs should accept the booster immunization in addition.
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