Perinatal transmission and manifestation of hepatitis C virus infection in a high risk population

We studied the perinatal transmission of hepatitis C virus (HCV) in 70 high risk mother/infant pairs. Seventy–six percent of the mothers (53 of 70) were coinfected with human immunodeficiency virus (HIV) and 79% (55 of 70) had a history of drug addiction. During the follow–up HCV RNA was detected in 14 of 70 (20%) infants: 12% (2 of 17) in infants born to HIV–negative mothers; and 23% (12 of 53) in infants to HIV–positive mothers. The rate of vertical transmission was significantly higher in vaginally delivered infants than in those delivered by cesarean section (32% vs. 6%; P <0.05). All 56 uninfected infants lost passively acquired anti–HCV by age 9 ± 4 months and only 2 of 56 infants (4%) had evidence of HIV infection. Four of 14 HCV RNA–positive infants (29%) had evidence of HTV coinfection. We observed 3 clinical patterns of HCV infection: a transient viremia in 2 infants; an acute pattern in 2 infants; and a chronic pattern in 10 infants. All 4 HIV–coinfected infants had chronic HCV infection. All infants with a chronic pattern, had increased alanine aminotransferase values for more than 6 months and 5 had a liver biopsy that showed signs of chronic persistent hepatitis. HCV perinatal transmission was more frequent in infants born to HIV–coinfected mothers than in infants born to HIV–noninfected women, particularly when delivered vaginally.