Hepatitis C virus (HCV) is the most common bloodborne virus in the United States. In some people, it can cause chronic hepatitis (persistent inflammation of the liver), cirrhosis (permanent scarring of the liver), and liver failure. Chronic HCV infection also increases risk for liver cancer. Strong antiviral drugs given for long periods (6 to 12 months) can make HCV disappear. These drugs are difficult to take and have many side effects. Doctors usually won't give them to people who drink too much, “shoot up” drugs, have severe liver disease or other serious medical problems, are pregnant or unwilling to practice contraception, or have severe psychiatric problems.