May is hepatitis awareness month. More than 5 million people in the U.S. are living with chronic hepatitis B or hepatitis C. But these two diseases receive limited attention in the general public and the health care system. Hepatitis C, for example, affects up to 3.9 million people, yet 75% are unaware they are infected. It's estimated that costs related to HCV infection will rise from $30 billion in 2009 to more than $85 billion in 2024.