The Facts
Hepatitis is the medical term for inflammation of the liver. Hepatitis may be acute (lasting only for the short term, after which a person recovers) or chronic (lasting for the long term). There are many causes of hepatitis, including viruses and alcoholism. Viral hepatitis is now a major cause of chronic hepatitis in North America. There are 5 hepatitis viruses: A, B, C, D, and E. There are also other viruses that can cause liver inflammation, like Epstein-Barr virus and cytomegalovirus, but these viruses are not called hepatitis viruses.
Hepatitis A and B (HAV and HBV) are common causes of liver inflammation in North America. There are about 30,000 new cases of HBV reported in the United States each year and 1.2 million people in the United States live with chronic HAV. Since many infected people have no symptoms, however, we can assume the true rate of infection is higher than this.
Among people born in North America, HAV is most common in children and young adults; HBV is most common in adults between the ages of 20 and 40 years old.