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 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. Some people have symptoms, which may last several weeks. In some cases, symptoms last up to 6 months. Sometimes the body is able to fight off the infection and the virus goes away. If the body isn’t able to fight off the virus, the virus does not go away, and chronic hepatitis B infection occurs.
Most healthy adults and children older than 5 years who have hepatitis B get better and do not develop a chronic hepatitis B infection.6
Chronic hepatitis B
Chronic hepatitis B is a long-lasting infection. Your chance of developing chronic hepatitis B is greater if you were 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, only about 5 percent of people first infected as adults develop chronic hepatitis B.6
How common is hepatitis B?
Hepatitis B worldwide
Hepatitis B infection is more common in some other parts of the world than it is in the United States. Though less than 0.5 percent of the U.S. population has hepatitis B, 2 percent or more of the population is infected in areas such as Africa, Asia, and parts of the Middle East, Eastern Europe, and South America.7,8,9
Hepatitis B infection has been especially common in some parts of the world, such as sub-Saharan Africa and parts of Asia, where 8 percent or more of the population was infected.9 In some of these areas, Hepatitis B infection rates are now lower than they were, but infection rates are still higher in these areas than in the United States.8,9
Hepatitis B in the United States
In the United States, about 862,000 people have chronic hepatitis B.6 Asian Americans and African Americans have higher rates of chronic hepatitis B than other U.S. racial and ethnic groups.10 Researchers estimate that about half of the people living with chronic hepatitis B in the United States are Asian Americans and Pacific Islanders.11 Chronic hepatitis B is also more common among people born in other countries than among those born in the United States.7
The hepatitis B vaccine has been available since the 1980s and, in 1991, doctors began recommending that children in the United States receive the hepatitis B vaccine. The annual rate of acute hepatitis B infections went down 88.5 percent between 1982 and 2015.12 In 2017, the annual number of hepatitis B infections rose in some states.13 Experts think the rise was related to increases in injection drug use. Injection drug use increases the risk of hepatitis B infection.
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 2 percent or more of the population has hepatitis B infection
- 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 8 percent or more of the population had hepatitis B infection
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 profession, such as health care, in which they have contact with blood, needles, or body fluids at work
- live or work in a care facility for people with developmental disabilities
- have diabetes
- have hepatitis C
- have lived in or travel often to parts of the world where hepatitis B is common
- have been on kidney dialysis
- live or work in a prison
- had a blood transfusion or organ transplant before the mid-1980s
In the United States, hepatitis B spreads among adults mainly through contact with infected blood through the skin, such as during injection drug use, and through sexual contact.12
Should I be screened for hepatitis B?
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 are infected with hepatitis B. Screening tests can help doctors diagnose and treat hepatitis B, which can lower your chances of developing serious health problems.
Your doctor may recommend screening for hepatitis B if you9,14
- are pregnant
- were born in an area of the world where 2 percent or more of the population has hepatitis B infection, which includes Africa, Asia, and parts of the Middle East, Eastern Europe, and South America
- didn’t receive the hepatitis B vaccine as an infant and have parents who were born in an area where 8 percent or more of the population had hepatitis B infection, which includes sub-Saharan Africa and parts of Asia
- 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 factors
What are the complications of hepatitis B?
Hepatitis B may lead to serious complications. Early diagnosis and treatment can lower your chances of getting complications.
Acute hepatitis B complications
Chronic hepatitis B complications
Chronic hepatitis B can lead to
- cirrhosis, a condition in which scar tissue replaces healthy liver tissue and prevents your liver from working normally. Scar tissue also partly blocks the flow of blood through the liver. As cirrhosis gets worse, the liver begins to fail.
- liver failure, in which your liver is badly damaged and stops working. Liver failure is also called end-stage liver disease. People with liver failure may require a liver transplant.
- liver cancer. Your doctor may suggest blood tests and an ultrasound or another type of imaging test to check for liver cancer. Finding cancer at an early stage improves the chance of curing the cancer.
Reactivated hepatitis B
In people who have ever had hepatitis B, the virus may become active again, or reactivated, later in life. When hepatitis B is reactivated, it may start to damage the liver and cause symptoms. Reactivated hepatitis B can lead to acute liver failure.
People at risk for reactivated hepatitis B include those who
- take medicines that reduce the activity of the immune system, such as
- chemotherapy to treat cancer
- medicines prescribed to treat conditions that involve the immune system, such as inflammatory bowel disease, rheumatoid arthritis, and psoriasis
- medicines prescribed for people receiving an organ transplant or bone marrow transplant
- corticosteroids, if taken for more than a few weeks
- take hepatitis C medicines
- have HIV infection
Doctors may test for current or past hepatitis B infection in people at risk for reactivated hepatitis B.
What are the symptoms of hepatitis B?
Many people infected with hepatitis B have no symptoms.
Some people with acute hepatitis B have symptoms 2 to 5 months after they come in contact with the virus.6 These symptoms may include
- dark yellow urine
- feeling tired
- gray- or clay-colored stools
- joint pain
- loss of appetite
- pain in the 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.6
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.
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 unclean water or untreated water that has not been boiled
- eating food that is unclean or has not been properly cooked
- 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
Mothers who have hepatitis B can safely breastfeed their babies. If a baby receives hepatitis B immune globulin (HBIG) and starts receiving the hepatitis B vaccine to prevent hepatitis B infection shortly after birth, hepatitis B is unlikely to spread from mother to child through breastfeeding.15
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
- whether the infection is acute or chronic
- whether you have an increased chance of liver damage
- whether the virus levels in your body are high or low
- 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 a person’s liver, a doctor may prescribe antiviral medicines to lower the chances of liver damage and complications.
Medicines that you take by mouth include
A medicine that doctors can give as a shot is peginterferon alfa-2a (Pegasys).
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, minor medical procedures, and surgery. If you have cirrhosis, you have an increased chance of liver cancer. Your doctor may order blood tests and an ultrasound or another type of imaging test to check for liver cancer.
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 or who have chronic liver disease 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. In some cases, doctors may recommend a different number or timing of vaccine shots.
If you are traveling to countries where hepatitis B is common and you haven’t received the hepatitis B vaccine, talk with your doctor and 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. Doctors typically recommend a dose of the hepatitis B vaccine to prevent infection. In some cases, doctors may also recommend a medicine called hepatitis B immune globulin (HBIG) to help prevent infection. You must get the vaccine dose and, if needed, 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, talk with your doctor about lowering the risk that the infection will spread to your baby. Your doctor will check your virus levels during pregnancy. If virus levels are high, your doctor may recommend treatment during pregnancy to lower virus levels and reduce the chance that hepatitis B will spread to your baby. Your doctor may refer you to a liver specialist to find out if you need hepatitis B treatment and to check for liver damage.
When it is time to give birth, tell the doctor and staff who deliver your baby that you have hepatitis B. 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. Obesity can increase the chance of nonalcoholic fatty liver disease (NAFLD), and NAFLD can increase liver damage in people who have hepatitis B. Talk with your doctor about healthy eating and maintaining a healthy weight.
You should also avoid alcohol because it can cause more liver damage.
Clinical Trials for Hepatitis B
The NIDDK conducts and supports clinical trials in many diseases and conditions, including liver diseases. The trials look to find new ways to prevent, detect, or treat disease and improve quality of life.
What are clinical trials for hepatitis B?
Clinical trials—and other types of clinical studies—are part of medical research and involve people like you. When you volunteer to take part in a clinical study, you help doctors and researchers learn more about disease and improve health care for people in the future.
Researchers are studying many aspects of hepatitis B, such as
- progression of hepatitis B and long-term outcomes
- new treatments for hepatitis B
- prevention of reactivated or worsening hepatitis B in people receiving cancer treatment
What clinical studies for hepatitis B are looking for participants?
You can view a filtered list of clinical studies on hepatitis B that are federally funded, open, and recruiting at www.ClinicalTrials.gov. You can expand or narrow the list to include clinical studies from industry, universities, and individuals; however, the NIH does not review these studies and cannot ensure they are safe. Always talk with your health care provider before you participate in a clinical study.
How is NIDDK- and NIH-funded research advancing the understanding of hepatitis B?
The NIDDK and the NIH have supported many research projects to learn more about hepatitis B, including the NIDDK’s Hepatitis B Research Network (HBRN). The HBRN, a network of 28 clinical sites throughout the United States and Canada, studies how hepatitis B affects children and adults and explores new approaches to diagnosis and treatment.
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 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:
Anna Suk-Fong Lok, M.D., University of Michigan