Quantitative Hepatitis B Surface Antigen Predicts Hepatitis B Transmission in Infants Born to e Antigen–positive Mothers

Supplemental Digital Content is available in the text. Goals: This study aimed to explore whether quantitative surface antigen [hepatitis B surface antigen (HBsAg)] can be used as a surrogate marker of hepatitis B virus (HBV) DNA to predict hepatitis B transmission before the first hepatitis vaccine dose in infants born to hepatitis B e antigen (HBeAg)-positive pregnant women. Background: Currently, HBV transmission persistently occurs worldwide, especially in infants born to e antigen (HBeAg)-positive highly viremic mothers. However, due to high cost, the extensive use of viral load testing to identify these high-risk mothers is limited. Materials and Methods: In total of 275 HBeAg-positive pregnant women paired with 280 infants were enrolled in this study. Quantitative HBsAg and HBV DNA levels were measured in the third trimester. Spearman rank correlation was used to assess the correlation between HBsAg levels and viral load, and multivariate logistic regression to identify factors related to HBV transmission in infants. Results: Among 280 infants included, 15 (5.4%) infants were infected with HBV. In this study, we observed that quantitative HBsAg was positively correlated with maternal viral load (r=0.70, P<0.001) and highly predicted HBV transmission in infants born to HBeAg-positive mothers with area under the curve of 0.76 (95% confidence interval, 0.71-0.81). The optimum threshold HBsAg levels above 4.6 log10 IU/mL to predict HBV transmission in infants had a sensitivity of 80.0%, specificity of 67.9%. Conclusions: Quantitative HBsAg could be used as a surrogate marker of HBV DNA levels to predict hepatitis B transmission occurring before the injection of first-dose vaccine in infants born to e antigen–positive mothers.