Protective effect of an improved immunization practice of mother-to-infant transmission of hepatitis B virus and risk factors associated with immunoprophylaxis failure

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Although routine immunoprophylaxis has been known to reduce hepatitis B virus (HBV) transmission, immunoprophylaxis failure still occurs. The study aimed to investigate the protective efficacy of an improved immunoprophylaxis protocol to prevent mother-to-infant transmission of HBV and to explore the potential risk factors associated with immunoprophylaxis failure and low antibody response. A prospective observational cohort study was conducted from July 2012 to April 2015. A total of 863 HBsAg-positive mothers and their 871 infants (8 pairs of twins) were included in the study. Two different hepatitis B vaccine doses (20 or 10 μg) were administered to the infants based on the hepatitis B e-antigen (HBeAg) status of their mothers. Simultaneously, hepatitis B immunoglobulin (HBIG) was administered to the infants. Initial injections of HBIG and the hepatitis vaccine were given within 2 hours after birth. Rates of HBV infections among the infants were evaluated at 7 months of age. Factors associated with immunoprophylaxis failure and low responses to vaccination were analyzed by unconditional logistic regression.. At 7 months of age, no immunoprophylaxis failure was observed in the 565 infants born to HBeAg-negative mothers. Among the 306 infants born to HBeAg-positive mothers, immunoprophylaxis failed in 16 infants (5.2%) of the infants and they were found to be HBsAg-positive. Further analysis showed that HBV DNA levels ≥108 IU/mL [odds ratio (OR) = 4.53, 95% confidence interval (95% CI): 1.19–17.34], delayed vaccination (OR = 4.14, 95% CI: 1.00–17.18), and inadequate initial injections (OR = 7.69, 95% CI: 1.71–34.59) were independently associated with immunoprophylaxis failure. Adequate titers of antibody to HBsAg (anti-HBs, ≥100 mIU/mL) were present in 96.5% of immunoprophylaxis-successful infants. For full-term infants, birth weights