SINCE 1982, CDC has been conducting intensive surveillance in collaboration with four sentinel counties (Denver County, Colorado; Jefferson County, Alabama; Pierce County, Washington; and Pinellas County, Florida) to determine trends in the epidemiology of acute viral hepatitis in the United States.
Hepatitis A (HA)—patient is positive for IgM antibody to hepatitis A virus (IgM anti-HAV).
Hepatitis B (HB)—patient is positive for hepatitis B surface antigen (HBsAg) and/or for IgM antibody to hepatitis B core antigen (IgM anti-HBc).
Non-A, non-B (NANB) hepatitis—patient is negative for IgM anti-HAV and negative for HBsAg and/or IgM anti-HBc.
From 1982 to 1985, both the overall incidence and the disease transmission patterns of HB were relatively constant. During that time, three major risk factors accounted for almost half of disease transmission: male homosexual activity was reported by an average of 21% of patients; intravenous (IV) drug abuse, by an average of 15%;