HBV and HCV infections pose a major public-health problem in the United States and are major causes of chronic liver disease. Three to five times more people are living with chronic viral hepatitis infections than with HIV infection. Table 1-2 presents the burden of HBV, HCV, and HIV infections in the United States. The US Centers for Disease Control and Prevention (CDC) estimates that 3.5–5.3 million people in the United States—1–2% of the population—are living with chronic HBV or HCV infection—about 800,000 to 1.4 million people with chronic hepatitis B and an additional 2.7–3.9 million people with chronic hepatitis C (CDC, 2009d). However, an accurate estimate is difficult to obtain because there is no national chronic-hepatitis surveillance program. Each year, about 15,000 deaths are caused by HBV- or HCV-associated liver cancer or end-stage liver disease (CDC, 2009d). Almost half the liver transplantations in the United States are necessitated by end-stage liver disease associated with HBV or HCV infection (Kim et al., 2009).
The annual costs of HBV and HCV infections are difficult to determine. The direct medical cost associated with HBV infection has been estimated at $5.8 million based on the number of new cases in 2000 among persons 5–24 years old (Chesson et al., 2004). An estimated $1.8 billion in medical care costs was associated with HCV infections in 1997 (Leigh et al., 2001). Indirect costs, such as lost productivity, add to the HCV-associated cost burden. Because of the aging of people now infected (including some people with asymptomatic infections who will become symptomatic), HCV-related illnesses, deaths, and costs are all expected to rise substantially during the next two decades (Pyenson et al., 2009; Wong et al., 2000).
The national strategy for preventing new HBV infection in infants and children—including routine screening of pregnant women for hepatitis B surface antigen (a blood marker for chronic HBV infection), universal infant hepatitis B immunization, and catchup vaccination of unvaccinated children and adolescents—has resulted in a dramatic reduction in chronic HBV infection in infants and acute HBV infection in children of all ethnicities (CDC, 2004; Mast et al., 2005, 2006). Despite those achievements, the goal of eliminating perinatal HBV transmission has not been achieved, largely because coverage of newborns with a birth dose of hepatitis B vaccine is incomplete (CDC, 2008c). As a result, CDC estimates that each year about 1,000 newborns develop chronic HBV infection, which puts them at risk for premature death from HBV-related liver disease (Ward, 2008b).