“Hepatitis” means inflammation of the liver. Hepatitis is most often caused by one of several viruses, such as hepatitis A virus, hepatitis B virus, or hepatitis C virus. Toxins, bacterial infections, certain drugs, other diseases, and heavy alcohol use can also cause hepatitis.

Hepatitis B is a contagious liver disease that results from infection with the hepatitis B virus. It can range in severity from a mild illness lasting a few weeks to a serious, lifelong illness. Hepatitis B can be either “acute” or “chronic”.

Acute hepatitis B virus infection is a short-term illness that occurs within the first 6 months after someone is exposed to the hepatitis B virus. Acute infection can—but does not always—lead to chronic infection.

Chronic hepatitis B virus infection is a long-term illness that occurs when the hepatitis B virus remains in a person’s body.

The number of acute hepatitis B virus infections has been declining each year, with an estimated 46,000 new infections in 2006. Many experts believe this decline is a result of widespread vaccination of children. However, up to 1.4 million people may have chronic hepatitis B, many of whom are unaware of their infection.

Hepatitis B is usually spread when blood, semen, or another body fluid from a person infected with the hepatitis B virus enters the body of someone who is not infected. This can happen through sexual contact with an infected person or sharing needles, syringes, or other drug-injection equipment. Hepatitis B can also be passed from an infected mother to her baby at birth.

Hepatitis B is not spread through breastfeeding, sharing eating utensils, hugging, kissing, holding hands, coughing, or sneezing. Unlike some forms of hepatitis, hepatitis B is not spread by contaminated food or water.

In the United States, hepatitis B is most commonly spread through sexual contact. The hepatitis B virus is 50–100 times more infectious than HIV and can be passed through the exchange of body fluids, such as semen, vaginal fluids, and blood.

Not everyone has symptoms with acute hepatitis B, especially young children. Most adults have symptoms that appear within 3 months of exposure. Symptoms can last from a few weeks to several months and include: fever, fatigue, nausea, loss of appetite, abdominal pain, joint pain, jaundice, dark urine and clay-colored bowel movements.

Many people with chronic hepatitis B remain symptom-free for up to 30 years, but others experience ongoing symptoms similar to those of acute hepatitis B. Chronic hepatitis B is a serious disease that can result in long-term health problems.

Doctors diagnose the infection using one or more blood tests. There is no medication available to treat acute hepatitis B, so doctors usually recommend rest, adequate nutrition, and fluids. People with chronic hepatitis B virus infection should be monitored regularly for signs of liver disease, and some people benefit from treatment with specific medications.

Over time, approximately 15%–25% of people with chronic hepatitis B develop serious liver problems, including liver damage, cirrhosis, liver failure and liver cancer. Every year, up to 4,000 people in the United States and more than 600,000 people worldwide die from hepatitis B-related liver disease.

The best way to prevent hepatitis B is by getting vaccinated. For adults, the hepatitis B vaccine series is usually given as 3 shots during a 6-month period. For treaveling individuals, the 3-shot series can be given over 3 weeks and a booster a year later. The entire series is needed for long-term protection. However, once a person has been infected with the hepatitis B virus, the vaccine does not provide protection against the disease.

Who should get vaccinated against hepatitis B?