• Twenty-three infants born to asymptomatic hepatitis B surface antigen (HBsAg) carrier mothers were followed up to determine the vertical transmission of hepatitis B virus. Four infants became positive for HBsAg within four months after birth. Three showed hepatic dysfunction; liver biopsy specimens demonstrated mild chronic hepatitis in one and persistent hepatitis in another. In six infants followed up for more than six months after birth, antibody to HBsAg (anti-HBs) without antigenemia could be detected. Antigenemia of cord blood strongly suggested that hepatitis B viral infection of the infant would occur. HBsAg was also demonstrated in breast milk by radioimmunoassay in three cases. These findings indicate that vertical transmission of hepatitis B virus occurs in many infants born to asymptomatic HBsAg carrier mothers, and that some of them become persistent carriers or develop chronic hepatitis without showing any signs suggesting hepatic involvement.
(Am J Dis Child 131:644-647, 1977)