Hepatitis C: a sleeping giant?

In the United States, non-A, non-B hepatitis accounts for 20-40% of acute viral hepatitis. Although it has traditionally been considered a transfusion-associated disease, non-A, non-B hepatitis is more likely to occur outside the transfusion setting. Surveillance data from the Centers for Disease Control show that in 1988 6% of patients with non-A, non-B hepatitis reported a history of blood transfusion, 46% parenteral drug use, 10% household or sexual exposure to a contact who had had hepatitis or exposure to multiple sex partners, 2% medical or dental employment involving frequent blood contact, less than 1% hemodialysis, and 40% no known source. Antibody to hepatitis C virus (anti-HCV) is found in the majority of patients with non-A, non-B hepatitis independent of the source of infection; however, antibody may not appear for 6 to 9 months after exposure or onset of illness. Limited serologic studies of the prevalence of anti-HCV in various population groups have found high anti-HCV rates (50-80%) in parenteral drug users and hemophiliacs, intermediate rates among the sexually active (5-15%), and low rates among health care workers (1%). In persons with acute or chronic hepatitis C, the presence of anti-HCV appears to indicate infectivity. Persons with no history of hepatitis who are anti-HCV positive may or may not be infectious. More sensitive and specific markers for the detection of hepatitis C virus will be needed to resolve this question.