Mother-to-infant transmission of hepatitis B virus: challenges and perspectives.

Chronic hepatitis B virus (HBV) infection due to perinatal mother-to-infant transmission (MTIT) remains a serious global health problem. Despite passive-active immunoprophylaxis using hepatitis B vaccination with or without hepatitis B immunoglobulin (HBIg), up to 8-10% of newborns still acquire HBV infection. Understanding the mechanisms of MTIT is essential for the interruption of HBV transmission. There are three possible routes of transmission: intrauterine transmission, transmission during delivery (intrapartum) and postnatal transmission through close contact or breast milk (postpartum). Overall, positivity for hepatitis B e antigen (HBeAg) and the high viral load of the mothers are the two most important risk factors related to MTIT of HBV. This article briefly reviews the viral factors related to MTIT of HBV and discusses the issues that warrant further investigation.