HEPATITIS-C VIRUS-INFECTION IN THE MOTHERS AND INFANTS COHORT STUDY

Objectives. To estimate the hepatitis C virus (HCV) vertical transmiss ion rate, the effect of potential risk factors, and the pattern of HCV antibody response and viremia in HCV-infected infants. Study Design. The Mothers and Infants Cohort Study enrolled both human immunodeficie ncy virus (HIV)-seropositive and HIV-seronegative pregnant women at fi ve obstetric clinics in New York City in a prospective cohort study be tween January 1986 and January 1991. HCV-infected mothers and their 12 2 offspring were followed-up for a minimum of 12 months for evidence o f HCV infection as determined by persistent HCV antibodies or detectio n of HCV RNA by reverse transcription polymerase chain reaction. Compa risons among groups for categorical variables were performed using the Fisher's exact test. Results. Seven (6%; 95% confidence interval, 2%- 11%) of the 122 infants were HCV-infected. There was a tendency for in creased risk of transmission with maternal viral and obstetrical facto rs, such as coinfection with HIV (7% vs 4%), high HIV viral load (13% vs 6%), HCV viremia (8% vs 3%), vaginal delivery (6% vs 0%), and femal e gender of offspring (8% vs 3%), although none of the associations re ached statistical significance. After loss of maternal antibody, HCV a ntibody seroconversion occurred at a mean age of 26 months in 3 HIV-co infected infants compared with 7 months of age in 4 HCV-infected HIV-u ninfected infants. Serial samples showed that HCV RNA persisted in 6 i nfants for at least 18 to 54 months. Conclusions. Our study is in acco rdance with other studies that have shown low overall HCV vertical tra nsmission risk and a trend toward higher risk with maternal risk facto rs such as HIV-coinfection or HCV viremia. A delay in infant HCV antib ody response may be associated with HIV coinfection although larger st udies are needed to confirm these findings.