Objective: To investigate the role of hepatitis B virus (HBV) DNA levels in HBV-carrier mother and selective transmission of HBV variant with S gene mutation to infant in the failure of neonatal HBV immunization.
Methods: Serum HBV DNA level was determined by Roche LightCycler quantities in 95 HBsAg-positive pregnant women and later in their newborns. Hepatitis B virus S gene sequences isolated from mother/child pairs were analyzed in 7 cases which did not respond to HBV vaccination and hepatitis B immunoglobulin.
Results: HBV infection was identified in 7.4 % of the infants during their first year after birth. The levels of HBV DNA in the mothers of the infected infants were higher than those of the uninfected group, and selective transmission of HBV variant from mother to infant was observed.
Conclusion: HBV DNA levels in HBV-carrier mother and selective transmission of HBV variant from mother to infant contribute to the failure of neonatal HBV immunization.