Prevention of chronic HBsAg carrier state in infants of HBsAg-positive mothers by hepatitis B immunoglobulin.

21 children of HBsAg-carrier mothers were given 0.5 ml/kg hepatitis B immunoglobulin (HBIg) within 48 h after birth and subsequently 0.16 ml/kg every month for 6 months; 20 children were not treated. None of the HBIg-treated children became HBsAg positive, compared with 5 of the untreated children (p less than 0.02). 2 of 3 children who were not started on HBIg until the fourth or fifth day after birth also became HBsAg positive. 4 children of mothers who had acute hepatitis B in the third trimester of pregnancy were treated with HBIg and remained HBsAg negative, whereas another, untreated, child became HBsAg positive.