Objective To explore the characteristics of HBV mother-to-child transmission, and the population diversity of HBV in children failure to HB vaccine and their mothers.
Methods Eight children who developed into chronic HBV infection after receiving hepatitis B vaccines and their respective mothers were enrolled into the research,the full length of HBV gene was amplified by PCR, the HBV gene was made to small fragments, different barcodes primers were attached to fragments by PCR, the 250–500 bp fragments were extracted from gel and sequenced by solexa sequencing technology. The sequencing data were analysised by statistical methods. Liver function, HBVM and HBV DNA level were determined for each patient.
Results (1) The sequences in paired mother and child could cluster well, the sequence homology between paired mother and child was beyond 99%. (2) The significant polymorphism positions existed in whole HBV gene among the children, and nt 200–300 and nt 700–800 in S, the Pre C, nt 1950–2100 in C and nt 2650–2850 in P genes were the hotter sites. (3) Significant polymorphism positions could be found in every immunised child. There were 10 significant polymorphism positions in “a” determinant region among 8 pairs. aa143 only existed in children and aa124 only existed in mother. The I126T and G145R in HBsAg “a” determinant region were demonstrated in two children.
Conclusions The HBV in children are delivered from their mothers, may be the most important reason for vaccine failure. The population diversity of HBV present in children failure to HB vaccine and their mothers.