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Hepatitis B Basics

CDC offers information on hepatitis B for both healthcare providers and the public, some of which is excerpted here. For more information, click the provided CDC links.

Hepatitis B FAQs for Health Professionals

Hepatitis B FAQs for the Public – CDC’s Division of Viral Hepatitis provides answers to questions about hepatitis B. We list some of the most common questions and answers. Find more questions and answers on the CDC Web site.

What is hepatitis B?

Hepatitis B is a contagious liver disease that ranges in severity from a mild illness lasting a few weeks to a serious, lifelong illness. It results from infection with the hepatitis B virus. 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.

How likely is it that acute hepatitis B will become chronic?

The likelihood depends upon the age at which someone becomes infected. The younger a person is when infected with hepatitis B virus, the greater his or her chance of developing chronic hepatitis B. Approximately 90 percent of infected infants will develop chronic infection. The risk goes down as a child gets older. Approximately 25–50 percent of children infected between the ages of 1 and 5 years will develop chronic hepatitis. The risk drops to 6–10 percent when the person infected is older than 5 years of age. Worldwide, most people with chronic hepatitis B were infected at birth or during early childhood.

How is hepatitis B spread?

Hepatitis B is spread when blood, semen, or other body fluid infected with the hepatitis B virus enters the body of a person who is not infected. People can become infected with the virus during activities such as:

  • Birth (spread from an infected mother to her baby during birth).
  • Sex with an infected partner.
  • Sharing needles, syringes, or other drug-injection equipment.
  • Sharing items such as razors or toothbrushes with an infected person.
  • Direct contact with the blood or open sores of an infected person.
  • Exposure to blood from needlesticks or other sharp instruments.

Can a person spread hepatitis B and not know it?

Yes. Many people with chronic hepatitis B virus infection do not know they are infected since they do not feel or look sick. However, they still can spread the virus to others and are at risk of serious health problems themselves.

Who is at risk for hepatitis B?

Although anyone can get hepatitis B, some people are at greater risk, such as those who:

  • Have sex with an infected person.
  • Have multiple sex partners.
  • Have a sexually transmitted disease.
  • Are men who have sexual contact with other men.
  • Inject drugs or share needles, syringes, or other drug equipment.
  • Live with a person who has chronic hepatitis B.
  • Are infants born to infected mothers.
  • Are exposed to blood on the job.
  • Are hemodialysis patients.
  • Travel to countries with moderate to high rates of hepatitis B.

If I think I have been exposed to the hepatitis B virus, what should I do?

If you are concerned that you might have been exposed to the hepatitis B virus, call your health professional or your health department. If a person who has been exposed to hepatitis B virus gets the hepatitis B vaccine and/or a shot called “HBIG” (hepatitis B immune globulin) within 24 hours, then hepatitis B infection may be prevented.

Does acute hepatitis B cause symptoms?

Sometimes. Although a majority of adults develop symptoms from acute hepatitis B virus infection, many young children do not. Adults and children older than 5 are more likely to have symptoms. Seventy percent of adults will develop symptoms from the infection.

What are the symptoms of acute hepatitis B?

Symptoms of acute hepatitis B, if they appear, can include:

  • Fever
  • Fatigue
  • Loss of appetite
  • Nausea
  • Vomiting
  • Abdominal pain
  • Dark urine
  • Clay-colored bowel movements
  • Joint pain
  • Jaundice (yellow color in the skin or the eyes)

Can a person spread hepatitis B without having symptoms?

Yes. Many people with hepatitis B have no symptoms, but these people can still spread the virus.

What are the symptoms of chronic hepatitis B?

Some people have ongoing symptoms similar to acute hepatitis B, but most individuals with chronic hepatitis B remain symptom free for as long as 20 or 30 years. Approximately 15–25 percent of people with chronic hepatitis B develop serious liver conditions, such as cirrhosis (scarring of the liver) or liver cancer. Even as the liver becomes diseased, some people still do not have symptoms, although certain blood tests for liver function might begin to show some abnormalities.

How will I know if I have hepatitis B?

Talk to your health professional. Since many people with hepatitis B do not have symptoms, doctors diagnose the disease by one or more blood tests. These tests look for the presence of antibodies or antigens and can help determine whether you:

  • Have acute or chronic infection.
  • Have recovered from infection.
  • Are immune to hepatitis B.
  • Could benefit from vaccination.

How serious is chronic hepatitis B?

Chronic hepatitis B is a serious disease that can result in long-term health problems, including liver damage, liver failure, liver cancer, or even death. Approximately 2,000–4,000 people die every year from hepatitis B-related liver disease.

How is acute hepatitis B treated?

There is no medication available to treat acute hepatitis B. During this short-term infection, doctors usually recommend rest, adequate nutrition, and fluids, although some people may need to be hospitalized.

How is chronic hepatitis B treated?

It depends. People with chronic hepatitis B virus infection should seek the care or consultation of a doctor with experience treating hepatitis B. This can include some internists or family medicine practitioners, as well as specialists such as infectious disease physicians, gastroenterologists, or hepatologists (liver specialists). People with chronic hepatitis B should be monitored regularly for signs of liver disease and evaluated for possible treatment. Several medications have been approved for hepatitis B treatment, and new drugs are in development. However, not every person with chronic hepatitis B needs to be on medication, and the drugs may cause side effects in some patients.

Can hepatitis B be prevented?

Yes. The best way to prevent hepatitis B is by getting the hepatitis B vaccine. The hepatitis B vaccine is safe and effective and is usually given as 3–4 shots during a 6-month period.

Who should get vaccinated against hepatitis B?

Hepatitis B vaccination is recommended for:

  • All infants, starting with the first dose of hepatitis B vaccine at birth.
  • All children and adolescents younger than 19 years of age who have not been vaccinated.
  • People whose sex partners have hepatitis B.
  • Sexually active persons who are not in a long-term, mutually monogamous relationship.
  • Persons seeking evaluation or treatment for a sexually transmitted disease.
  • Men who have sexual contact with other men.
  • People who share needles, syringes, or other drug-injection equipment.
  • People who have close household contact with someone infected with the hepatitis B virus.
  • Health care and public safety workers at risk for exposure to blood or blood-contaminated body fluids on the job.
  • People with end-stage renal disease, including predialysis, hemodialysis, peritoneal dialysis, and home dialysis patients.
  • Residents and staff of facilities for developmentally disabled persons.
  • Travelers to regions with moderate or high rates of hepatitis B.
  • People with chronic liver disease.
  • People with HIV infection.
  • Anyone who wishes to be protected from hepatitis B virus infection.

To reach individuals at risk for hepatitis B, vaccination is also recommended for anyone in or seeking treatment from the following:

  • Sexually transmitted disease treatment facilities
  • HIV testing and treatment facilities
  • Facilities providing drug-abuse treatment and prevention services
  • Health care settings targeting services to injection drug users
  • Health care settings targeting services to men who have sex with men
  • Chronic hemodialysis facilities and end-stage renal disease programs
  • Correctional facilities
  • Institutions and nonresidential day care facilities for developmentally disabled persons

Are pregnant women tested for hepatitis B?

Yes. When a pregnant woman comes in for prenatal care, she will be given a series of routine blood tests, including one that checks for the presence of hepatitis B virus infection. This test is important because women infected with this virus can pass hepatitis B to their babies during birth. But this can be prevented by giving the infant HBIG and the first hepatitis B vaccine at birth, and then completing the series.

Do babies need the hepatitis B vaccine even if a pregnant woman does not have hepatitis B?

Yes. The hepatitis B vaccine is recommended for all infants. CDC recommends that the infant get the first shot before leaving the hospital.

Last Updated: 
9/1/15