AASLD Nov 2005
Brian R. Edlin, Weill Medical College of Cornell University, New York, NY

…of these, approximately 3.4 million are currently infected (chronic HCV)…. 

Background: The number of persons in the United States who have been infected with hepatitis C virus (HCV) has been estimated at 3.9 million, including 2.7 million currently infected. These estimates were derived from the National Health and Nutrition Examination Survey (NHANES), however, which excludes
several high-risk populations from its sampling frame. The true number of HCV infections in the United States is therefore unknown. 

Methods: Using data from the U.S. Census, the Centers for Medicare & Medicaid Services, the Bureau of Justice Statistics, and the published medical literature, we estimated the number of persons in five populations groups excluded from the NHANES sampling frame and the prevalence of HCV antibodies in each: incarcerated persons, homeless persons, hospitalized persons, active duty military, and nursing home residents. We used the NHANES estimate for the proportion of antibody-positive persons who are currently infected (73.9%). 

Results: An estimated 800,000 to 1,200,000 persons excluded from the NHANES sampling frame have HCV antibody, of whom 733,000 (592,000 to 868,000) are currently infected. 

Conclusions: The number of U.S. residents who have been infected with HCV is probably 800,000 to 1,200,000 higher than the 3.9 million NHANES estimate, or approximately five million. Of these, approximately 3.4 million are currently infected.