What is hepatitis B?
Hepatitis B is a viral infection that causes liver inflammation and damage. Inflammation is swelling that occurs when tissues of the body become injured or infected. Inflammation can damage organs.
Viruses invade normal cells in your body. Many viruses cause infections that can be spread from person to person. The hepatitis B virus spreads through contact with an infected person’s blood, semen, or other body fluids.
The hepatitis B virus can cause an acute or chronic infection.
Acute hepatitis B
Acute hepatitis B is a short-term infection. If you have symptoms, they may last several weeks. In some cases, symptoms last up to 6 months. Sometimes your body is able to fight off the infection and the virus goes away. Most healthy adults and children older than 5 years old who have hepatitis B get better without treatment.5
Chronic hepatitis B
Chronic hepatitis B is a long-lasting infection. Chronic hepatitis B occurs when your body isn’t able to fight off the virus and the virus does not go away.
Your chances of developing chronic hepatitis B are greater if you are infected with the virus as a young child. About 90 percent of infants infected with hepatitis B develop a chronic infection. About 25 to 50 percent of children infected between the ages of 1 and 5 years develop chronic infections. However, among people infected during adulthood, only about 5 percent develop chronic hepatitis B.5
How common is hepatitis B?
Researchers estimate that about 850,000 to 2.2 million people in the United States have chronic hepatitis B. In 1991, doctors began recommending that children in the United States receive the hepatitis B vaccine. Since then, the rate of new hepatitis B infections has gone down 82 percent.5 Asian Americans and African Americans have higher rates of chronic hepatitis B.6 Many people in the United States who have chronic hepatitis B were infected before the vaccine became available.
Chronic hepatitis B is more common in Africa, Asia, and parts of the Middle East, Eastern Europe, and South and Central America than it is in the United States.7 Chronic hepatitis B infection has been especially common in some parts of the world, including sub-Saharan Africa, parts of Asia, and the Pacific Islands.5,8 Use of the hepatitis B vaccine has helped lower infection rates in some of these areas.7,9
Who is more likely to get hepatitis B?
People are more likely to get hepatitis B if they are born to a mother who has hepatitis B. The virus can spread from mother to child during birth. For this reason, people are more likely to have hepatitis B if they
- were born in a part of the world where hepatitis B is more common
- were born in the United States, didn’t receive the hepatitis B vaccine as an infant, and have parents who were born in an area where hepatitis B was especially common
In the United States, 47 to 95 percent of people with chronic hepatitis B were born outside the United States, in parts of the world where hepatitis B is more common.8
People are also more likely to have hepatitis B if they
- are infected with HIV, because hepatitis B and HIV spread in similar ways
- have lived with or had sex with someone who has hepatitis B
- have had more than one sex partner in the last 6 months or have a history of sexually transmitted disease
- are men who have sex with men
- are injection drug users
- work in a field, such as health care, in which they have contact with blood, needles, or body fluids at work
- have lived in or travel often to parts of the world where hepatitis B is common
- have been on kidney dialysis
- are taking medicines that weaken the immune system, such as steroids or chemotherapy medicines
- have worked or lived in a prison
- had a blood transfusion or organ transplant before the mid-1980s
In the United States, sexual contact is the most common way that hepatitis B spreads among adults.6 Injection drug use is another important way that hepatitis B spreads. Since 2009, the number of acute hepatitis B infections has risen in some Appalachian states, especially among adults who inject drugs.10
Should I be screened for hepatitis B?
Your doctor may recommend screening for hepatitis B if you
- are pregnant
- were born in an area of the world where chronic hepatitis B is more common
- didn’t receive the hepatitis B vaccine as an infant and have parents who were born in an area where chronic hepatitis B was especially common, such as sub-Saharan Africa, parts of Asia, or the Pacific Islands
- are HIV positive
- have injected drugs
- are a man who has sex with men
- have lived with or had sex with a person who has hepatitis B
- have an increased chance of infection due to other factors8,11
Screening is testing for a disease in people who have no symptoms. Doctors use blood tests to screen for hepatitis B. Many people who have hepatitis B don’t have symptoms and don’t know they have hepatitis B. Screening tests can help doctors diagnose and treat hepatitis B, which can lower your chances of developing serious health problems.
What are the complications of hepatitis B?
Chronic hepatitis B may lead to complications, including cirrhosis, liver failure, and liver cancer. Early diagnosis and treatment of chronic hepatitis B can lower your chances of developing these complications.
Cirrhosis is a condition in which the liver slowly deteriorates and is unable to function normally. Scar tissue replaces healthy liver tissue and partially blocks the flow of blood through the liver. In the early stages of cirrhosis, the liver continues to function. As cirrhosis gets worse, the liver begins to fail.
Also called end-stage liver disease, liver failure progresses over months, years, or even decades. With end-stage liver disease, the liver can no longer perform important functions or replace damaged cells.
Having chronic hepatitis B increases your chance of developing liver cancer. Your doctor may suggest an ultrasound test to check for liver cancer every 6 months. Finding cancer at an early stage improves the chance of curing the cancer.
What are the symptoms of hepatitis B?
Some people infected with hepatitis B have no symptoms. Some people have symptoms of acute hepatitis B within 2 to 5 months after they come in contact with the virus.1 These symptoms may include
- dark yellow urine
- feeling tired
- gray- or clay-colored stools
- joint pain
- loss of appetite
- pain in your abdomen
- yellowish eyes and skin, called jaundice
Infants and children younger than age 5 typically don’t have symptoms of acute hepatitis B. Older children and adults are more likely to have symptoms.5
If you have chronic hepatitis B, you may not have symptoms until complications develop, which could be decades after you were infected. For this reason, hepatitis B screening is important, even if you have no symptoms.
If you have ever had hepatitis B, certain medicines may cause the hepatitis B virus to begin damaging your liver and causing symptoms. These medicines include
- immunosuppressants—medicines that weaken your immune system—which doctors prescribe to treat many diseases, including cancer, rheumatoid arthritis, and inflammatory bowel disease
- hepatitis C medicines
Your doctor may test you for hepatitis B before you begin taking these medicines, even if you have no hepatitis B symptoms.
What causes hepatitis B?
The hepatitis B virus causes hepatitis B. The hepatitis B virus spreads through contact with an infected person’s blood, semen, or other body fluids. Contact can occur by
- being born to a mother with hepatitis B
- having unprotected sex with an infected person
- sharing drug needles or other drug materials with an infected person
- getting an accidental stick with a needle that was used on an infected person
- being tattooed or pierced with tools that were used on an infected person and weren’t properly sterilized, or cleaned in a way that destroys all viruses and other microbes
- having contact with the blood or open sores of an infected person
- using an infected person’s razor, toothbrush, or nail clippers
You can’t get hepatitis B from
- being coughed on or sneezed on by an infected person
- drinking water or eating food
- hugging an infected person
- shaking hands or holding hands with an infected person
- sharing spoons, forks, and other eating utensils
- sitting next to an infected person
A baby can’t get hepatitis B from breast milk.12
How do doctors diagnose hepatitis B?
Doctors diagnose hepatitis B based on your medical and family history, a physical exam, and blood tests. If you have hepatitis B, your doctor may perform additional tests to check your liver.
Medical and family history
Your doctor will ask about your symptoms and about factors that may make you more likely to get hepatitis B. Your doctor may ask whether you have a family history of hepatitis B or liver cancer. Your doctor may also ask about other factors that could damage your liver, such as drinking alcohol.
During a physical exam, your doctor will check for signs of liver damage such as
- changes in skin color
- swelling in your lower legs, feet, or ankles
- tenderness or swelling in your abdomen
What tests do doctors use to diagnose hepatitis B?
Doctors use blood tests to diagnose hepatitis B. Your doctor may order additional tests to check for liver damage, find out how much liver damage you have, or rule out other causes of liver disease.
Your doctor may order one or more blood tests to diagnose hepatitis B. A health care professional will take a blood sample from you and send the sample to a lab.
Certain blood tests can show whether you are infected with hepatitis B. If you are infected, your doctor may use other blood tests to find out
- if the infection is acute or chronic
- whether you have an increased chance of liver damage
- whether you need treatment
If you have chronic hepatitis B, your doctor will recommend testing your blood regularly because chronic hepatitis B can change over time. Even if the infection is not damaging your liver when you are first diagnosed, it may damage your liver in the future. Your doctor will use regular blood tests to check for signs of liver damage, find out if you need treatment, or see how you are responding to treatment.
Blood tests can also show whether you are immune to hepatitis B, meaning you can’t get hepatitis B. You may be immune if you got a vaccine or if you had an acute hepatitis B infection in the past and your body fought off the infection.
If you’ve had chronic hepatitis B a long time, you could have liver damage. Your doctor may recommend additional tests to find out whether you have liver damage, how much liver damage you have, or to rule out other causes of liver disease. These tests may include
- blood tests
- transient elastography, a special ultrasound of your liver
- liver biopsy, in which a doctor uses a needle to take a small piece of tissue from your liver
Doctors typically use liver biopsy only if other tests don’t provide enough information about a person’s liver damage or disease. Talk with your doctor about which tests are best for you.
How do doctors treat hepatitis B?
Doctors typically don’t treat hepatitis B unless it becomes chronic. Doctors may treat chronic hepatitis B with antiviral medicines that attack the virus. Not everyone with chronic hepatitis B needs treatment. If blood tests show that hepatitis B could be damaging your liver, your doctor may prescribe antiviral medicines to lower your chances of liver damage and complications.
Medicines that you take by mouth include
- entecavir (Baraclude)
- telbivudine (Tyzeka)
- tenofovir alafenamide (Vemlidy)
- tenofovir disoproxil fumarate (Viread)
Medicines that doctors can give as shots include
The length of treatment varies. Hepatitis B medicines may cause side effects. Talk with your doctor about the side effects of treatment. Tell your doctor before taking any other prescription or over-the-counter medicines.
How do doctors treat the complications of hepatitis B?
If chronic hepatitis B leads to cirrhosis, you should see a doctor who specializes in liver diseases. Doctors can treat the health problems related to cirrhosis with medicines, surgery, and other medical procedures. If you have cirrhosis, you have an increased chance of liver cancer. Your doctor may order an ultrasound test to check for liver cancer every 6 months.
If chronic hepatitis B leads to liver failure or liver cancer, you may need a liver transplant.
How can I protect myself from hepatitis B infection?
You can protect yourself from hepatitis B by getting the hepatitis B vaccine. If you have not had the vaccine, you can take steps to reduce your chance of infection.
Hepatitis B vaccine
The hepatitis B vaccine has been available since the 1980s and should be given to newborns, children, and teens in the United States. Adults who are more likely to be infected with hepatitis B should also get the vaccine. The hepatitis B vaccine is safe for pregnant women.
Doctors most often give the hepatitis B vaccine in three shots over 6 months. You must get all three shots to be fully protected.
If you are traveling to countries where hepatitis B is common and you haven’t received the hepatitis B vaccine, try to get all the shots before you go. If you don’t have time to get all the shots before you travel, get as many as you can. Even one shot may give you some protection against the virus.
Reduce your chance of infection
You can reduce your chance of hepatitis B infection by
- not sharing drug needles or other drug materials
- wearing gloves if you have to touch another person’s blood or open sores
- making sure your tattoo artist or body piercer uses sterile tools
- not sharing personal items such as toothbrushes, razors, or nail clippers
- using a latex or polyurethane condom during sex
Prevent infection after contact with the virus
If you think you have been in contact with the hepatitis B virus, see your doctor right away. A dose of the hepatitis B vaccine and, in some cases, a medicine called hepatitis B immune globulin (HBIG), may protect you from getting sick. You must get the vaccine dose and HBIG shortly after coming into contact with the virus, preferably within 24 hours.
How can I prevent spreading hepatitis B to others?
If you have hepatitis B, follow the steps above to avoid spreading the infection. Your sex partners should get a hepatitis B test and, if they aren’t infected, get the hepatitis B vaccine. You can protect others from getting infected by telling your doctor, dentist, and other health care professionals that you have hepatitis B. Don’t donate blood or blood products, semen, organs, or tissue.
Prevent hepatitis B infections in newborns
If you are pregnant and have hepatitis B, tell the doctor and staff who deliver your baby. A health care professional should give your baby the hepatitis B vaccine and HBIG right after birth. The vaccine and HBIG will greatly reduce the chance of your baby getting the infection.
Eating, diet, and nutrition for hepatitis B
If you have hepatitis B, you should eat a balanced, healthy diet. Talk with your doctor about healthy eating. You should also avoid alcohol because it can cause more liver damage.
This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings through its clearinghouses and education programs to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.
The NIDDK would like to thank:
Paul Martin, M.D., University of Miami Miller School of Medicine