ABSTRACTIt is unclear whether a mother who is negative for hepatitis B virus surface antigen (HBsAg) but positive for hepatitis B virus (HBV) is at potential risk for mother-to-child transmission of HBV. This study, using a paired mother-teenager population, aimed to assess whether maternal HBsAg-negative HBV infection (hnHBI) is a significant source of child HBV infection (HBI). A follow-up study with blood collection has been conducted on the 93 mother-teenager pairs from the initial 135 pregnant woman-newborn pairs 13 years after neonatal HBV vaccination. Serological and viral markers of HBV have been tested, and phylogenetic analysis of HBV isolates has been done. The HBI prevalence was 1.9% (1hnHBI/53) for teenage children of non-HBI mothers, compared with 16.7% (1hnHBI/6) for those ofhnHBI mothers and 2.9% (1 HBsAg-positive HBV infection [hpHBI]/34) for those ofhpHBI mothers. Similar viral sequences have been found in one pair of whom both the mother and teenager have hadhnHBI. In comparison with thehpHBI cases, those withhnHBI had a lower level of HBV load and a higher proportion of genotype-C strains, which were accompanied by differentiated mutations (Q129R, K141E, and Y161N) of the “a” determinant of the HBV surface gene. Our findings suggest that mother-to-teenager transmission ofhnHBI can occur among those in the neonatal HBV vaccination program.
Immune response to hepatitis B virus surface antigen peptides during HBV infection