Incidence of acute hepatitis B--United States, 1990-2002.

Hepatitis B virus (HBV) is a bloodborne and sexually transmitted virus that is acquired by percutaneous and mucosal exposure to blood or other body fluids of an infected person. Clinical manifestations of acute hepatitis B can be severe, and serious complications (i.e., cirrhosis and liver cancer) are more likely to develop in chronically infected persons. In the United States, approximately 1.2 million persons have chronic hepatitis B virus (HBV) infection and are sources for HBV transmission to others. However, since the late 1980s, the incidence of acute hepatitis B has declined steadily, especially among vaccinated children. To characterize the epidemiology of acute hepatitis B in the United States, CDC analyzed national notifiable disease surveillance data for 1990-2002. This report summarizes the results of that analysis, which indicated that, during 1990-2002, the incidence of reported acute hepatitis B declined 67%. This decline was greatest among children and adolescents, indicating the effect of routine childhood vaccination. The decline was lowest among adults, who accounted for the majority of cases; incidence increased among adults in some age groups. To reduce HBV transmission further in the United States, hepatitis B vaccination programs are needed that target men who have sex with men (MSM), injection-drug users (IDUs), and other adults at high risk.