All three can result in chronic infection that places the individual at risk for chronic liver disease or primary hepatocellular carcinoma. The serologic exclusion of the known hepatitis viruses continues to leave cases of hepatitis that clinically appear to be viral in origin. Estimates of acute disease burden viral hepatitis, United States, 1997. Hepatitis A virus is an RNA virus classified in the Picornavirus family. Chronic HAV infection does not occur.
Most transmission is by the fecal-oral route leading to spread between close contacts.
Hepatitis A is vaccine preventable. Many of these patients may have acquired their infection from household contact with persons, especially children, with asymptomatic or unrecognized infection. Vaccination of persons at increased risk for hepatitis A will have little effect on national disease rates, because most cases do not occur among persons in these groups. To achieve a sustained reduction in national incidence of hepatitis A, widespread routine vaccination is needed. Vaccination of successive cohorts of young children should significantly lower the incidence of hepatitis A over time and eventually provide the opportunity to eliminate HAV transmission.