OBJECTIVEIn order to investigate the characterization of mother to children transmission, the sequences of HBV were analyzed to offer the information about the effect of interrupt.

METHODSThe sera of 75 mother with positive HBsAg are collected from 2003, and the ELISA was performed to determine the HBV infection of the child. The Large S sequence of HBV including preS and S gene are amplified and sequenced. The genotype was determined with the standard genotype sequence. The mutation ratios of group successfully interrupted and failed compared.

RESULTSThe sera of 4 pairs mother-children were HBsAg positive, including one twins. The virus genes are successful amplified. Four of HBV genotype is B and one is C. Gene of twins has mutation of T143M. 43 HBV of successfully interrupted group were sequenced. There are 37 of genotype B and 6 of genotype C. Three have the mutation in "a" dominant, and the percentage is 7%.

CONCLUSIONMost failed interrupted child have the same sequence with their mother, and the ratio is higher than the mother of successful group, however there have no statistical significance.