Vaccines and Your Immune System

Hepatitis B

What Is Hepatitis B? Symptoms, Causes, Diagnosis, Treatment, and Prevention

By Medically Reviewed by 
Reviewed:
Medically Reviewed
Hepatitis B is an infection of the liver that’s caused by the hepatitis B virus (HBV). Some people will develop a short-term (acute) infection, which lasts for less than six months, before their bodies fight off the virus. If someone isn’t able to fight off the hepatitis B virus, it will cause a long-lasting (chronic) infection, which lasts for six months or longer. Some people with hepatitis B will develop a lifelong infection.

Hepatitis B is one of five main viral types of hepatitis. The others are hepatitis A, C, D, and E.

Getting vaccinated can protect you against HBV.

Signs and Symptoms of Hepatitis B

Many people who have hepatitis B don’t experience any symptoms of the infection. Younger children — particularly those under age 5 — are unlikely to show any signs or symptoms of an acute infection, whereas up to half of older children and adults will experience signs of acute hepatitis B.

Most people who have chronic hepatitis B don’t experience any symptoms of the virus for many years, or even decades.

The symptoms of both acute and chronic hepatitis B, which can range from mild to severe, include:

  • Fever
  • Fatigue and weakness
  • Loss of appetite
  • Abdominal pain
  • Dark-colored urine
  • Clay-colored stools
  • Jaundice (yellow coloring in the skin or eyes)
  • Joint pain
When the symptoms of hepatitis B occur, they generally appear about one to four months after catching the virus.

Many people will feel sick for a few weeks, although others can be ill for up to six months.


Learn More About Signs and Symptoms of Hepatitis B

Causes and Risk Factors of Hepatitis B

Hepatitis B is spread when the blood, semen, or other bodily fluid of an infected person enters the body of someone who doesn’t have the virus.

In the United States, the infection is mainly spread through blood, including during injection drug use and through sex.

Here are the ways hepatitis B can be spread:

  • Through sex with a partner who has the virus
  • By sharing needles, syringes, or other drug equipment with someone who has the virus
  • During birth, when an infected mother passes the virus to her baby
  • By sharing toothbrushes, razors, nail clippers, or other items with an infected person
  • Through accidental needle stick injuries that occur from an infected person
  • Making direct contact with an infected person’s blood or open sores
  • Getting a tattoo or piercing from a contaminated needle
Hepatitis B is not spread by hugging, kissing, breastfeeding, sharing eating utensils, shaking hands, or being coughed or sneezed on.

Some people are more at risk for infection than others. Hepatitis B testing is recommended for:

  • People who were born in countries with high rates of hepatitis B
  • People who were born in the United States, but weren’t vaccinated as infants, to parents who were from countries with high rates of hepatitis B
  • Men who have sex with men
  • People who work in a job where they’re exposed to blood (such as healthcare workers)
  • People who inject drugs
  • People who have HIV
  • People who live with people who have hepatitis B
  • People who are sexually active with someone who has hepatitis B
  • Pregnant women
  • Infants who are born to mothers with hepatitis B
  • People who are now or have been incarcerated in jail, prison, or other detention setting
  • People who have a sexually transmitted infection and/or multiple sex partners
  • People who are on immunosuppressive therapy
  • People with high liver enzyme levels
  • People with certain health conditions, such as hepatitis C or end-stage renal disease

How Is Hepatitis B Diagnosed?

Hepatitis B can be diagnosed with a blood test. If you do have the infection, further blood tests can determine whether it is acute or chronic and whether you’re likely to experience liver damage and need treatment.

Other blood tests can determine whether you’re immune to the virus, either because you received a hepatitis B vaccine in the past or were previously infected with the virus and fought it off. Once your body fights off hepatitis B, you can’t be reinfected with the virus. However, some people who were infected in the past can become sick if the virus “reactivates.” Reactivation is rare, but there is a risk of it happening if your immune system is suppressed.

If you suspect that you have hepatitis B or are showing symptoms of the infection, talk to your doctor about being tested.

Your doctor may want to screen you for hepatitis B if you have risk factors for the virus — for example, if you’re pregnant or HIV-positive — even if you aren’t showing symptoms.

Prognosis of Hepatitis B

While there is a vaccine that can prevent hepatitis B, there is no cure. But treatments for chronic hepatitis B can often help prevent the virus from causing liver damage.

The risk that an acute hepatitis B infection will become chronic (and therefore cause serious complications) decreases as a person gets older. About 90 percent of infants who get hepatitis B will develop a chronic infection; the virus will become chronic in about 25 to 50 percent of children ages 1 to 5. Of the people who get hepatitis B as a child, about 25 percent may die from cirrhosis or liver cancer.

About 95 percent of adults will completely recover from hepatitis B and won’t develop a long-lasting infection. Approximately 15 percent of people who get hepatitis B after childhood may die of cirrhosis or liver cancer.

Duration of Hepatitis B

Hepatitis B can be an acute or chronic infection. People who have acute hepatitis B — meaning it lasts less than six months — will clear the infection from their body and likely make a full recovery.

This is the case for about 95 percent of people who catch the virus as an adult.

A chronic hepatitis B infection lasts for longer than six months and possibly a lifetime. About 90 percent of infants who get hepatitis B will develop a chronic infection.

The symptoms of hepatitis B may not appear until a person’s liver disease becomes severe, which can take years (if not decades) to occur.

Treatment and Medication Options for Hepatitis B

Treatment for a short-term infection generally includes rest, good nutrition, and lots of fluids.

But people with severe symptoms may need to be hospitalized and given antiviral medications to avoid complications.

Chronic hepatitis B can’t be cured, but it can be managed with antiviral medications and interferon injections, which help reduce the risk of liver disease and other complications. Not everyone who has hepatitis B needs treatment; others may need treatment for the rest of their life.

If the infection has caused severe liver damage, you may be eligible for a liver transplant (a healthy liver that has been donated).

Medication Options

There are multiple antiviral medications — which can help fight the virus and prevent it from damaging your liver — available to take by mouth, including:

An interferon injection, peginterferon alfa-2b (Pegasys), works by decreasing the amount of hepatitis B virus that is in the body and is used primarily in younger people with the infection or in women who want to become pregnant in a few years (though it should not be used during pregnancy itself).

Learn More About Treatment for Hepatitis B

Prevention of Hepatitis B

The best way to prevent hepatitis B is by getting the vaccine, which has been available since the 1980s and is given to newborns, children, and teenagers in the United States, usually in three shots over a six-month period of time.


The vaccine doesn’t contain any live virus and therefore can’t cause hepatitis B.

Babies born to women with hepatitis B should receive the hepatitis B vaccine as well as the hepatitis B immune globulin (HBIG) injection right after birth to prevent the infection from taking hold.

If you haven’t been vaccinated, you can reduce your risk of getting hepatitis B by using protection during sex, not using illegal drugs (or, if you can’t stop, using a sterile needle each time you inject drugs), and making sure that the person who gives you a tattoo or body piercing uses clean equipment and sterile needles.

Complications of Hepatitis B

Acute hepatitis B usually doesn’t cause serious complications. However, in rare instances, people can experience liver failure; their liver stops working, and they may need a liver transplant.

Chronic hepatitis B can lead to serious complications, such as cirrhosis, a condition in which scar tissue accumulates on the liver, preventing the organ from working properly and eventually causing liver failure. The infection can also lead to liver cancer, as well as kidney disease or inflammation in the blood vessels.

Research and Statistics: Who Has Hepatitis B?

About 880,000 people in the United States live with chronic hepatitis B. Worldwide, hepatitis B affects an estimated 296 million people.

Hepatitis B is likely underreported. In 2020, a total of 2,157 cases of acute (short-term) hepatitis B were reported to CDC. Since many people may not have symptoms or don’t know they are infected, their illness is often not diagnosed, so it isn’t reported or counted. The CDC estimates the actual number of acute hepatitis B cases was closer to 14,000 in 2020.

Less than 0.5 percent of people in the United States have hepatitis B. In other countries, 2 percent or more of the population has the virus. These areas include Africa and Asia as well as parts of the Middle East, Eastern Europe, and South America.

Rates of acute hepatitis B infections fluctuate. In 2020, after a decade of stable rates, the rate of acute hepatitis B abruptly decreased by 32 percent after 2019.  Yet acute hepatitis C cases have increased 124 percent over the same period, and they increased 15 percent from 2019 to 2020. So vaccinations and testing are still very important.

Asian Americans and Hepatitis B

Asian Americans have an increased risk for acquiring chronic hepatitis B. Approximately 1 in 12 Asian Americans in the United States have chronic hepatitis B, compared to about 1 in 1,000 white Americans, which is one of the largest racial health disparities in the country.

The Office of Minority Health, within the U.S. Department of Health and Human Services, notes that approximately half of the people in the United States with chronic hepatitis B are Asian or Pacific Islanders. And Asian Americans were almost 8 times more likely to die from hepatitis B compared to white Americans.

Related Conditions and Causes of Hepatitis B

If you have hepatitis B, you’re at risk for hepatitis D, a virus that is also spread through bodily fluids. (You can’t get hepatitis D unless you have hepatitis B).

Other types of viral hepatitis include: hepatitis A and E, which are generally acquired from contaminated foods and drinks, and hepatitis C, which is most commonly spread through blood.

Resources We Love

Centers for Disease Control and Prevention (CDC)

The CDC provides information for both medical providers and the public about hepatitis B, as well as statistics on national trends in infection rates.

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

A part of the National Institutes of Health, the NIDDK conducts research about liver disease (among other conditions) and keeps the public informed about hepatitis B.

Hepatitis B Foundation

This nonprofit advocacy group works to improve quality of life for people with Hepatitis B. On their site, you’ll find news on the latest research, links to online support groups, and more.

Additional reporting by Joseph Bennington-Castro.

Editorial Sources and Fact-Checking

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