Hepatitis C: prevalence, transmission, screening, and prevention.

Hepatitis C virus (HCV) infection affects 185 million individuals worldwide and nearly 4 million Americans. In the United States, it causes more deaths each year than HIV. Mortality rates from HCV are expected to increase as the baby boomer generation ages because these individuals have the highest prevalence of HCV infection. Injection drug use is the most common mode of transmission. Sexual transmission (most common among men who have sex with men), perinatal transmission, occupational exposures among health care workers, and tattooing are less common modes of transmission. In at least 21% of HCV-positive individuals, no risk factors for infection are identified. The Centers for Disease Control and Prevention, along with the US Preventive Services Task Force, recommends that all individuals born between 1945 and 1965 undergo one-time screening for HCV regardless of risk factors. Individuals at particular risk of acquiring HCV also should be screened. The goal of screening is to identify and, if appropriate, treat HCV-positive individuals before the infection progresses and causes hepatic fibrosis, liver failure, hepatocellular carcinoma, or other complications. Several factors predict progression, including age at infection, sex, ethnicity, genetics, alcohol consumption, and HIV serostatus.