Vertical transmission of hepatitis C virus infection.
Vertical transmission of hepatitis C virus (HCV) was studied in 58 infants of 55 mothers (3 sets of twins). HCV RNA analyses by the polymerase chain reaction (PCR) and alanine aminotransferase (ALT) were performed on consecutive blood samples from birth to 18 months of age (0, 3, 9 and 18 months). Data on factors possibly influencing mother-to-infant transmission of HCV, such as concomitant human immunodeficiency virus (HIV) and hepatitis B virus infection during pregnancy, maternal HCV RNA status at delivery, mode of delivery, prematurity and breastfeeding habits were collected. In addition, 6 older siblings (age 4-10 years) of the infants were tested once for anti-HCV. Of the 55 mothers 52 (95%) had a history of intravenous drug use (IVDU). Two mothers were HIV positive. 40/54 (75%) tested mothers were HCV RNA positive. 16 (27%) infants were delivered by Caesarean section, and 50 (86%) infants were breastfed. All infants were HCV RNA negative on all occasions and anti-HCV negative at the age of 18 months. Maternally acquired anti-HCV antibodies disappeared and were not detected by 9 months in 78%. One of the 6 older siblings was anti-HCV and HCV RNA positive. We conclude that the risk of vertical HCV transmission is low in infants of HCV-positive/HIV-negative mothers, and that breastfeeding seems to be safe in this group.