Hepatitis G

Overview
Hepatitis G and GB virus C (GBV-C) are RNA viruses that were independently identified in 1995, and were subsequently found to be two isolates of the same virus. (GB-A and GB-B are probably Tamarin viruses, while GB-C infects humans.)

Although GBV-C was initially thought to be associated with chronic hepatitis, extensive investigation failed to identify any association between this virus and any clinical illness.

GBV-C is, phylogenetically, closely related to hepatitis C virus, but appears to replicate primarily in lymphocytes, and poorly if at all in hepatocytes.

The majority of immune-competent individuals appear to clear GBV-C viraemia within the first few years following infection and although the time interval between GBV-C infection and clearance of viraemia (detection of GBV-C RNA in plasma) is not known, infection may persist for decades in some individuals.

Approximately 2% of healthy US blood donors are viraemic with GBV-C, and up to 13% of blood donors have antibodies to E2 protein, indicating prior infection.

Parenteral, sexual and vertical transmission of GBV-C have all been documented, and because of shared modes of transmission, individuals infected with HIV are commonly co-infected with GBV-C. Among people with HIV infection, the prevalence of GBV-C viraemia ranges from 14 to 43%.

Some studies have suggested that co-infection with HGV will actually slow the progression of Hepatitis C and HIV.