POSSIBLE ROLE OF HIGH-TITER MATERNAL VIREMIA IN PERINATAL TRANSMISSION OF HEPATITIS-C VIRUS

To study perinatal transmission of hepatitis C virus (HCV), 15 anti-HC V-positive carrier mothers without human immunodeficiency virus coinfe ction were recruited. At delivery, maternal blood was taken and anti-H CV titer was determined and HCV RNA measured in each serum sample by r everse transcription polymerase chain reaction (PCR). A competitive PC R was used in selected samples to quantitate HCV concentration. The 15 neonates were followed regularly for 1 year and their sera were also assayed for anti-HCV and for HCV RNA by reverse transcription PCR. All the mothers were positive for HCV RNA. Only one normal spontaneously delivered neonate of a mother with extremely high titer of anti-HCV (1 :20,000) and HCV concentration (10(10) copies/mL) had both anti-HCV an d HCV RNA in serum for up to 6 months of age. In contrast, none of the remaining 14 neonates born to mothers with low- to high-titer anti-HC V (1:4-1:1000) and moderate amounts of HCV RNA (10(5)-10(6) copies/mL) contracted HCV infection. The results imply that high-titer maternal viremia and normal spontaneous delivery may allow more HCV to infect t he neonate intrapartum, therefore establishing perinatal transmission.