While many viruses can affect the liver as part of their spread through the body (for example, the infectious mononucleosis virus), some viruses primarily infect the liver. There are 5 well-characterized types of viral hepatitis: A, B, C, D, and E. All viral forms of hepatitis can be spread from one person to another, although the mode of transmission may differ for each. Hepatitis C affects more than 180 million people worldwide. Chronic hepatitis C is now the most common reason for liver transplantation and the leading cause in the United States for developing liver cancer.

Hepatitis A (which is spread by contaminated food and water or in conditions of poor hygiene) and hepatitis B (transmitted through blood-to-blood contact) are also very widespread. A single person may be infected with more than one type of hepatitis. Because of the risk of additional liver damage, you should ask your doctor or nurse about getting vaccinations against hepatitis A and hepatitis B.

When you have hepatitis C, you must avoid alcohol and talk to your doctor or nurse about all medications or other drugs you are taking. You are at risk of liver inflammation, and potentially increased liver damage, caused by drinking and inhaled or swallowed toxins or medications.

For information about hepatitis C, including its causes, how it develops, and how to prevent its spread, see What Is Hepatitis C?

Find out more about hepatitis A.

Find out more about hepatitis B.

Learn more about other forms of hepatitis.

About Hepatitis A

Hepatitis A is very common in the U.S. population: 1 out of 3 Americans has been infected at some point. Most people who are exposed to hepatitis A recover completely without treatment and, once the infection has subsided, develop lifelong immunity to the disease.

Because it is so common, people without a medical background may think of hepatitis A first when they hear "hepatitis." You may want to be proactive and explain the differences between the A and C forms of the condition to those close to you.

Hepatitis A is transmitted primarily by the fecal-to-oral route through contaminated food or water, or because of poor hygiene. Hepatitis A can also be contracted by eating shellfish from contaminated water sources.

People who are infected with hepatitis A generally develop flu-like symptoms, such as low-grade fever, aches, and mild abdominal pain within 10 to 40 days after exposure. For some people, these flu-like symptoms may be followed by jaundice (a yellowing of the eyes and skin). Most people recover from hepatitis A on their own without treatment. However, in fewer than 1% of cases, severe hepatitis A infections may progress to liver failure and to a need for liver transplantation. Hepatitis A does not lead to the development of chronic hepatitis, cirrhosis (scarring of the liver), or liver cancer.

A vaccine is available to protect against hepatitis A. It is generally recommended for anyone who has hepatitis C, because an additional liver infection may cause more serious problems to develop.

You can reduce the likelihood of contracting hepatitis A by washing your hands with warm water and soap, particularly after using the toilet or changing diapers, and before preparing and eating food. Good hygiene practices are especially important for anyone who works with food.

About Hepatitis B

Hepatitis B is transmitted through blood or blood products, through sexual contact, or from mother to child during childbirth.

Hepatitis B is less common that hepatitis C, but many people don't have a clear understanding of the difference. When you talk about hepatitis C, some people may be thinking of hepatitis B and assume that you have a sexually transmitted disease because hepatitis B is a type of viral hepatitis more easily transmitted sexually. Acquiring hepatitis C through sexual contact is uncommon. You may or may not want to address this issue directly with those close to you—but it is something to keep in mind.

In the United States, an estimated 1.25 million people are chronically infected with hepatitis B. According to the U.S. Centers for Disease Control and Prevention (CDC), about 30% of people who are infected with hepatitis B do not have any symptoms of the disease. Others may experience flu-like symptoms, including low-grade fever, aches, and mild abdominal pain.

Although individuals with healthy immune systems usually recover from hepatitis B on their own after about 6 months, 5% to 10% of those who are infected are at risk of developing the chronic (long-term) form of the disease. Most often those with long-term infection have no symptoms, although some people may suffer from fatigue, malaise, and periods of jaundice. If left untreated, these individuals may be at risk for serious complications of liver damage such as cirrhosis, liver failure, or liver cancer. Severe hepatitis B can be treated with interferon products, lamivudine, other antiviral drugs such as adefovir, or a combination of drugs.

A highly effective vaccine has been developed to help protect against hepatitis B. Currently, the CDC is supporting a universal childhood vaccination program with the goal of eliminating the spread of hepatitis B altogether. In general, the vaccine is recommended for people with hepatitis C.

The risk of hepatitis B transmission can be lowered by carefully cleaning up blood and blood products, practicing safe sex, and not sharing needles, razors, or other personal care items (such as toothbrushes and nail clippers) that might come into contact with blood. To help prevent mother-to-child transmission, all pregnant women should be tested for the hepatitis B virus. Newborns of mothers who are hepatitis-B-positive must be vaccinated against the condition and receive other precautionary treatments at the time of birth.

Other Forms of Hepatitis

Hepatitis D is only found in people with hepatitis B (since the hepatitis D virus needs the hepatitis B virus to reproduce). It is treated in the same way as hepatitis B. Hepatitis D infection is often seen as a "complication" of hepatitis B because it may make the original hepatitis B infection worse but cannot be treated on its own. The highest infection rates are seen in Africa, Southern Italy, Greece, Eastern Europe, and South America.

Hepatitis E, like hepatitis A, is spread primarily in contaminated food and water. Hepatitis E is rare in the United States but has occurred in epidemics in India, Pakistan, China, Northern and Central Africa, and Central America. The infection has been seen in tourists returning from travel to those areas. The body usually clears this virus naturally over the course of several weeks.

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