Hepatitis B mother--to--child transmission.

Approximately 350 million people are estimated to be chronically infected with hepatitis B virus, leading to an important public health problem. In highly endemic areas where 8 to 15% of people are chronically infected with hepatitis B virus, the risk for the neonate to be perinatally infected by the chronically infected mother, then to become chronically infected themselves, is very high. In those countries, the World Health Organization recommends hepatitis B vaccination systematically at birth, independent of hepatitis B virus maternal status. This vaccination program has begun to induce a rapid decrease in the number of acute hepatitis B virus infections and has also had a secondary effect of a decrease in related sequels. Lamivudine (Zeffix, GlaxoSmithKline), when associated with the immunization of the neonate, was recently demonstrated to dramatically reduce the residual risk of perinatal transmission. In intermediate and low endemicity areas, a systematic hepatitis B surface antigen screening is recommended during pregnancy, allowing, in the case of positivity, a selective hepatitis B virus neonate immunization during the first 12 h of life. Hepatitis B virus vaccination of children born to hepatitis B surface antigen-positive mothers confers long-term immunity.