How does hepatitis B affect the body?

Most people who have hepatitis B have an acute (short-term) infection.

• They start to feel better after 2 to 3 weeks and recover completely after 4 to 8 weeks. They develop antibodies to hepatitis B. These antibodies provide lifelong protection against future infection.
• Only some people (mainly older adults) have long-lasting symptoms.
• A small number of people have symptoms that last for months and sometimes years.

If you stay infected with the virus for 6 months or longer, you have a chronic infection. The risk of having chronic infection is related to the age at which you first become infected. The risk is highest for newborns infected at birth and children up to age 5.

Many people who have chronic hepatitis B won't develop complications. But about 15 to 25 out of 100 people who have chronic infection will die of cirrhosis or liver cancer. (This means that 75 to 85 people out of 100 who have a chronic infection won't die of these diseases.) Having a lot of virus in the body (a high viral load) increases the risk of getting cirrhosis and liver cancer.

• You are more likely to get cirrhosis if you carry a certain hepatitis B antigen, are older than 40 and have high liver enzymes.
• Risk factors for getting liver cancer after chronic infection include being male, having a family history of liver cancer, being over 40 years old, having cirrhosis and also having hepatitis C.

Hepatitis D (delta) virus infection is a problem that can develop in relation to hepatitis B infection, but it's not common. It occurs only in those with hepatitis B. And it may make that infection more severe.

People who have hepatitis B who engage in high-risk behavior (such as having multiple sex partners or injecting illegal drugs) are at increased risk for hepatitis C. They also are at higher risk of getting human immunodeficiency virus (HIV), the virus that causes acquired immunodeficiency syndrome (AIDS).