Sporadic non-A, non-B hepatitis: frequency and epidemiology in an urban U.S. population.

Patients with acute viral hepatitis were identified at five hospitals in Baltimore, Maryland between February 1979-August 1980. Of the 295 patients with serologically diagnosed hepatitis, 42% had non-A, non-B hepatitis; 48% had hepatitis B; and 10% had hepatitis A. Compared with matched control patients with no liver disease, patients with non-A, non-B hepatitis more often had received a blood transfusion (11% vs. O, P less than 0.001), used parenteral drugs (42% vs. 4%, P less than 0.001), were employed as health workers in direct patient care or hospital laboratory work (6% vs. 3%, P less than 0.05), had personal contact with others who had hepatitis (16% vs. 1%, P less than 0.001), or had ingested raw shellfish (34% vs. 20%, P less than 0.01). A history of previous clinical hepatitis and serologic markers indicating previous hepatitis B infection were found in patients with non-A, non-B hepatitis more often than in the control patients. Chronic non-A, non-B hepatitis was found in 34 (42.5%) of 80 patients with non-A, non-B hepatitis.