Community acquired viral hepatitis B and C in the United States.

In the United States, most reported cases of hepatitis B occur in adults as a result of behavioural, lifestyle, or occupational exposures, but a significant number of children also become infected in well defined settings. Although only 1-3% of acute hepatitis B virus (HBV) infections occur in children under 5 years of age, they account for 20-30% of all chronic infections. A new strategy for HBV prevention in the USA includes integration of HBV vaccine into childhood immunisation schedules. Vaccination strategies that target high risk groups have not been effective. To determine the frequency and severity of community acquired chronic hepatitis C, patients with acute non-A, non-B hepatitis identified in four sentinel counties in the United States were followed prospectively. Hepatitis C virus (HCV) infection was found in 106 (82%) of 130 patients. Ninety three per cent of the HCV positive patients had a risk factor for their infection: 59% parenteral, 6% sexual or household, and 28% low socioeconomic level. Chronic hepatitis developed in 62%, independently of the risk factor for infection. HCV-RNA persisted in most patients, including those with biochemical resolution of their hepatitis. This study suggests that HCV may be a major cause of liver disease and persistent viraemia in the United States.