Acute Viral Hepatitis: United States
The three most common forms of acute viral hepatitis in the United States declined dramatically between 1995 and 2005, with hepatitis A and B at the lowest levels ever. The main factor behind the declines in new cases of hepatitis A and B were the availability of vaccines and strong federally supported immunization programs. Declines in new cases of hepatitis A were greater among children in the 17 states where routine vaccination of children has been recommended since 1999. The declines in hepatitis B were greatest among children and teens age 15 and younger, likely the result of high vaccination coverage in this age group. Declines in reported new cases of hepatitis C were likely due to reductions in high-risk behaviors among injection drug users, as well as efforts to diagnose individuals infected with hepatitis C and the promotion of health behaviors to reduce person-to-person transmission of the virus.
The reported cases of acute hepatitis B also dropped to the lowest rate ever recorded in 2005 (1.8/100,000), a decline of 79% from 1990. In addition to the declines noted in children, hepatitis B rates also declined among adults but remained highest among those 25 to 44 years of age and among people with behavioral risk factors such as high-risk sexual activity and injection drug use. Cases of hepatitis C have also declined steadily since the late 1980s. However, this trend should be viewed with caution since surveillance for acute hepatitis C is limited because many individuals do not immediately develop symptoms and do not know they are infected with the virus.