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Harvard Health Publications

Hepatitis B

What Is It?

Hepatitis is inflammation of the liver. Hepatitis B is hepatitis caused by the hepatitis B virus.

Hepatitis B virus spreads through contact with infected blood. Specifically, hepatitis B may be spread through:

  • Direct contact with the blood of an infected person

  • Unprotected sexual activity with an infected person

  • Needle sharing among intravenous drug users

  • Sharing razors or other personal items with an infected person

  • Being pierced or tattooed with contaminated instruments

  • Blood transfusions (extremely rare in the United States because of improved testing)

  • Childbirth, when the virus is passed from mother to child

Hepatitis B

Immunization with the hepatitis B vaccine can greatly reduce the risk of hepatitis B.

The hepatitis B virus can cause temporary or long-term (chronic) hepatitis. The initial infection with the virus may not even cause symptoms.

People that do develop symptoms following initial infection with the virus have acute hepatitis. Most of them will clear the virus from their liver and blood.

But a minority of people will develop a long-term infection. This is called chronic hepatitis. In chronic hepatitis, the symptoms of hepatitis often disappear then come back later. People with chronic hepatitis remain infectious. They can pass on the virus to others.

Some people are not able to rid their body of the infection. But they do not have any symptoms of disease. These people are called carriers. They also can pass the infection to others.


The initial symptoms of acute hepatitis B vary. They can include:

  • Loss of appetite

  • Nausea

  • Vomiting

  • Fatigue

  • Headache

  • Fever

  • Itching

  • Weight loss

  • Abdominal pain

  • Sleep disturbance

  • Loss of sex drive

These symptoms may be followed by jaundice. Jaundice is a yellowing of the eyes and skin, and a darkening of the urine.

Most people recover from acute hepatitis. They are no longer infected with the virus when their illness ends.

However, about one in ten adults may develop chronic hepatitis. They remain infected by the virus, can develop chronic liver disease, and can pass the virus to other people.

People with chronic hepatitis may be free of symptoms for long periods. But symptoms eventually reappear. Symptoms, when they do occur, may include:

  • Fatigue

  • Jaundice (yellow color of the skin and eyes)

  • An ill feeling

  • Decreased appetite

  • Aching joints

A small number of people with chronic hepatitis develop liver cirrhosis. This is scarring of the liver that results in poor liver function. They may develop symptoms of advanced liver disease, including:

  • Jaundice

  • Fluid accumulation inside the abdomen

  • Swelling of the legs

  • Confusion

  • Gastrointestinal bleeding

People with hepatitis B who develop cirrhosis are at risk of developing liver cancer.


Your doctor will ask about any potential exposures to hepatitis B. This includes any illegal drug use or unprotected sexual activity. Your doctor will examine your skin, eyes, and abdomen for evidence of fluid accumulation. He or she will estimate the size of your liver.

Your doctor will order blood tests. These check your liver function, and can spot liver damage.

Blood tests can also confirm a hepatitis B diagnosis. They detect the presence and amount of hepatitis B virus in the blood. The tests also detect antibodies to the virus. Antibodies are proteins produced by your immune system to attack the virus.

People who have completely recovered from an acute hepatitis B infection usually have antibodies in their blood. But they do not have any detectable virus. People with acute or chronic hepatitis who have an active infection usually have detectable levels of virus in their blood.

Your doctor may suspect that you have significant liver damage. In this case, he or she may recommend a liver biopsy. In a biopsy, a small amount of tissue is removed and examined in a laboratory. It helps determine whether you are developing signs of cirrhosis.

Expected Duration

Most people recover from an acute infection within 3 months. People may feel well during this time. But it may take up to 4 months before hepatitis B virus is no longer detected in the blood.

Chronic hepatitis B can be treated with a variety of medications. However, it rarely is cured.


You can prevent hepatitis B infection by avoiding exposure to the virus:

  • Don't share needles for injecting intravenous drugs

  • Don't have unprotected sex

In the United States and many other countries, hepatitis B vaccine is offered to all children. Adults at high risk of exposure also should be immunized. These include medical personnel.


There is no cure for acute hepatitis B. Rather, treatment is aimed at reducing the amount of virus in the body, and easing the inflammation that causes the symptoms.

In rare cases, an episode of acute hepatitis B can be unusually severe. It may require hospitalization. A very small number of people with acute infection will develop liver failure. They require a liver transplant to prevent death.

Doctors treat chronic hepatitis B with antiviral medications when there is evidence of persistent virus activity accompanied by ongoing inflammation and/or scarring of the liver. Antiviral drugs commonly prescribed are entecavir and tenofovir.

People with chronic liver disease that continues to worsen can be considered for a liver transplant. This procedure can be lifesaving.

When To Call a Professional

Call your doctor if you develop symptoms of hepatitis B. Severe symptoms may require hospital treatment.

If you have a chronic hepatitis B infection and you develop symptoms of advanced liver disease, seek immediate medical attention. Symptoms of advanced liver disease include:

  • Swelling in your abdomen and legs

  • Confusion

  • Jaundice


Severe acute hepatitis B can occur in a small number of cases, and can sometimes be fatal.

In most cases of acute hepatitis B, people recover completely after the short-term infection. However, a small percentage of patients go on to develop chronic hepatitis B.

In people with chronic hepatitis B, the outlook depends upon the severity of liver inflammation, the amount of scarring (cirrhosis) and response to antiviral treatment. People with mild liver damage who have no virus detected in the blood have a better prognosis.

External resources

American Liver Foundation
75 Maiden Lane, Suite 603
New York, NY 10038
Phone: 212-668-1000
Toll-Free: 1-800-465-4837
Fax: 212-483-8179

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