"Hepatitis" means inflammation of the liver. Hepatitis is most often caused by a virus. Heavy alcohol use, toxins, some medications, and certain medical conditions can also cause hepatitis. In the United States, the most common types of viral hepatitis are hepatitis A, hepatitis B and hepatitis C. (Download CDC's The ABCs of Hepatitis .)
When first infected with a hepatitis virus, a person can develop an “acute” infection, which can last from a few days to 6 months. Acute infections can range in severity from a very mild illness with few or no symptoms to a serious condition requiring hospitalization. Hepatitis A, which is spread through close contact with an infected person or contaminated food or drinks, causes only acute infection.
A percentage of people infected with hepatitis B or hepatitis C, which are spread through contact with infected blood, develop “chronic,” or lifelong, infection. Over time, chronic viral hepatitis can lead to serious liver problems, including liver damage, cirrhosis, liver failure, or liver cancer. Chronic viral hepatitis is the leading cause of liver cancer and the most common reason for liver transplantation. An estimated 5.3 million Americans are living with chronic hepatitis. Because the virus may not cause symptoms for 20 or 30 years, most do not know they are infected.
Thanks to public health efforts like hepatitis A and B vaccination, screening of the blood supply, and improved infection-control practices, new hepatitis infections have declined dramatically in the United States. Currently, key hepatitis efforts are focused on promoting vaccination and prevention strategies for populations at risk and encouraging testing to help people who are infected learn their status and get beneficial treatment. Because up to three-fourths of people living with hepatitis C virus were born during 1945-1965, most of whom do not know they are infected, CDC is focusing testing efforts on this population. Early diagnosis and treatment can help prevent chronic hepatitis from progressing to liver disease.
The liver is one of the largest and most important organs. It is about the size of a football and weighs about three pounds in the average-sized person. The liver is located on the upper right side of the body, behind the lower ribs. Almost all the blood in the body passes through the liver. The liver performs hundreds of functions, including storing nutrients; removing waste products and worn-out cells from the blood; filtering and processing chemicals in food, alcohol and medications; and producing bile, a solution that helps digest fats and eliminate waste products.
CDC's Division of Viral Hepatitis (DVH) is part of CDC's National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention . In collaboration with domestic and global partners, DVH provides the scientific and programmatic foundation and leadership for the prevention and control of hepatitis virus infections and their manifestations.
DVH consists of three branches — the Epidemiology and Surveillance Branch, the Prevention Branch, and the Laboratory Branch — that work collaboratively to prevent viral hepatitis infections and associated liver disease. Learn More 
Know More Hepatitis Campaign Materials
Hepatitis Online Risk Assessment Tool
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Hepatitis Testing Day - May 19
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