The past incidence of hepatitis C virus infection: Implications for the future burden of chronic liver disease in the United States

Because chronic liver disease may develop many years after acute hepatitis C virus (HCV) infection, the past incidence of acute infections is a major determinant of the future burden of HCV-associated complications. We estima ted Bast incidence of acute HCV infection using national seroprevalence dat a and relative age-specific incidence data from a sentinel counties surveil lance system. Projections of the future prevalence of HCV-infected patients were derived from models that included an 85% drop in HCV infection incide nce as observed for reported cases in the early 1990s. The models showed a large increase in the incidence of HCV infections from the late 1960s to th e early 1980s. The degree of increase was dependent on the assumed rate of antibody loss; a model with 2.5% annual antibody loss showed annual inciden ce increasing from 45,000 infections (95% confidence interval [95% CT]: 0-1 10,000) in the early 1960s to 380,000 infections (94% CI: 250,000 to 500,00 0) in the 1980s, Projections showed that although the prevalence of HCV inf ection may be declining currently because of the decline in incidence in th e 1990s, the number of persons infected for greater than or equal to 20 yea rs could increase substantially before peaking in 2015, If the incidence of new HCV infections does not increase in the future, persons born between 1 940 and 1965 will be at highest lifetime risk of acquiring the infection.