Methods HBV DNA S gene were amplified by polymerase chain reaction(PCR) in sera from 36 children with HBsAg positive after immunized with hepatitis B vaccine. The PCR products were sequenced.

• 方法收集乙肝疫苗免疫后HBsAg阳性的儿童血清标本36份,利用聚合酶链反应(PCR)扩增HBV S基因片段,对PCR产物进行脱氧核糖核酸(DNA)序列测定。