2000 Indiana Report of Infectious Diseases
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Rates presented are per 100,000 population and are based on the U.S. 2000 Census.
In 2000, no cases identified in Indiana met the case definition of acute hepatitis C. In 2000, the following changes were made to national surveillance case definition:
- serum transferase levels must now be 7 times the upper limit of normal
- positive hepatitis C antibody tests must be verified by a more specific assay.
An acute case of hepatitis C must now meet the following criteria:
- discrete onset of illness,
- jaundice or serum aminotransferase levels greater than 7 times the upper limit,
- serological tests negative for hepatitis A and hepatitis B,
- antibody to hepatitis C virus verified by an additional more specific assay.
In the U.S., in 2000, the reported acute hepatitis C incidence rate was approximately 1.2 per 100,000 population. Reporting of acute hepatitis C is unreliable for monitoring incidence of acute infection, because no serologic marker is available to diagnose acute hepatitis C, and persons testing positive for antibody to hepatitis C may be reported as having acute hepatitis C without the necessary clinical information to confirm acute disease. In addition, approximately 80% of persons newly infected have no signs or symptoms of infection and are not diagnosed. It is estimated that the number of new infections per year has declined from an average of 240,000 in the 1980s to about 40,000 in 1998. Most new infections are associated with illegal injection drug use.
Reporting requirements for hepatitis C in Indiana changed in October 2000. In addition to physicians and hospitals who are still required to report acute cases of hepatitis C, laboratories now must report positive antibody to hepatitis C (anti-HCV) by Enzyme Immunoassay (EIA), Recombinant Immunoblot Assay (RIBA), and RNA tests. Until October 2000, laboratory surveillance of positive tests was voluntary. There were 4,936 newly identified persons reported as testing positive for at least one of the reportable tests. Of these, 2,790 (57%) reported positive results from the EIA test, but specific confirmatory testing was not reported. Of these reports, 58% were for males, 32% were for females, and 10% did not identify sex. Age was unknown for 88% of the identified persons. The case rates were highest for persons ages 40-49 (197/100,000 population) followed by those ages 30-39 (101).
It is estimated that 3.9 million Americans have been infected with the hepatitis C virus, and 2.7 million of these individuals are chronically infected. Chronically infected persons are at increased risk for death from liver disease.