Transmission of Hepatitis C: Sexual, Vertical or Exclusively Blood–Borne?

Abstract

Serum samples from eight pregnant women and their offspring were studied by nested polymerase chain reaction (PCR) for detection of hepatitis C virus (HCV) RNA to evaluate mother–to–child transmission of this virus. The mothers were all infected with human immunodeficiency virus (HIV); none showed symptoms of HCV infection. Anti–HCV antibodies were tested for by recombinant immunoblot assay. HCV viral sequences were found in five of the mothers and four of eight children, three of them at birth. Viremia was persistent in one infant who had chronic transaminase elevation and persistently remained anti–HCV–positive. The other three babies had intermittent viremia; all were asymptomatic and lost anti–HCV antibodies during follow–up. This loss of antibodies was also observed in PCR–negative infants. Thus, these results demonstrate transmission of HCV from mother to child by women coinfected with HCV and HIV. They indicate the usefulness of PCR for direct and early detection of HCV viremia in neonates. Body fluids from 14 patients with chronic hepatitis C were analyzed for the presence of hepatitis C viral RNA using the polymerase chain reaction. Nucleic acids were extracted from serum, saliva, and semen in guanidinium thiocyanate, subjected to reverse transcription, and then amplified by a double polymerase chain reaction technique using “nested” primers from the highly conserved 5′ noncoding region of the hepatitis C virus genome. Hepatitis C viral RNA was found in the serum of all patients in titers ranging between 10^-1 and 10^-3. The hepatitis C viral genome was not detected in any saliva or semen sample. These findings suggest that body fluids of patients with chronic hepatitis C are rarely, if ever, contaminated with the hepatitis C virus. This may help to explain the infrequent transmission of this disease by sexual or close physical contact.