Hepatitis B Basics

Key points

  • Hepatitis B is a liver disease caused by the hepatitis B virus (HBV).
  • HBV infection can be short (acute) or long-term (chronic).
  • About 1 in 2 people with hepatitis B do not know they are infected.
  • HBV is contagious and spreads through contact with infected blood and body fluids.
  • Vaccination is the best way to prevent infection.
An illustration showing the hepatitis b virus in the liver

About Hepatitis B

Hepatitis B is a vaccine-preventable liver infection caused by HBV. HBV is transmitted when blood, semen, or another body fluid from a person infected with the virus enters the body of someone who is uninfected.

Hepatitis B can range from a mild, short-term, acute illness lasting a few weeks to a serious, long-term, chronic infection.


The type of hepatitis B you have depends on how long you have had the virus in your body, the health of your liver, and other factors. A blood test will indicate which one you have.

Acute hepatitis B

Acute hepatitis B is a short-term illness that occurs within the first 6 months after exposure to HBV. Some people with acute hepatitis B have no symptoms or only a mild illness. For others, acute hepatitis B can cause a more severe illness that requires hospitalization.

Fast facts about acute hepatitis B

  • In 2022, 52% of all acute hepatitis B cases were people ages 40–59 years.
  • The rate of newly reported acute hepatitis B cases remained stable during 2022.
  • Rates of acute hepatitis B were highest among non-Hispanic Black people.
  • Rates of acute hepatitis B were highest in states in or near the Appalachian region.

Chronic hepatitis B

Acute hepatitis B can lead to a lifelong infection known as chronic hepatitis B. Left untreated, chronic hepatitis B can cause serious health problems, including liver damage, cirrhosis, liver cancer, and even death.

Fast facts about chronic hepatitis B

  • CDC estimates that about 640,000 adults in the US have chronic (long-term) hepatitis B.
  • In 2022, the highest rate of chronic hepatitis B was in non-Hispanic Asian and Pacific Islander people.
  • In 2022, the rate of newly reported chronic hepatitis B cases was 11 times higher among non-Hispanic Asian/Pacific Islander persons than among non-Hispanic White people.

Signs and symptoms

Many people infected with hepatitis B virus won’t experience symptoms. If symptoms occur during acute infection, they often begin 90 days after exposure. Although the symptoms of acute HBV infection and chronic HBV infection may be similar, most people with chronic infection do not have symptoms until much later in life, often decades after exposure.


You can have hepatitis B even if you don't have any symptoms.

Symptoms of hepatitis B include:

  • Dark urine or clay-colored stools
  • Feeling tired
  • Fever
  • Joint pain
  • Loss of appetite
  • Nausea, stomach pain, throwing up
  • Yellow skin or eyes (jaundice)

Learn more about hepatitis B symptoms.

How it spreads

Hepatitis B is primarily spread when blood, semen, or certain other body fluids – even in microscopic amounts – from a person infected with HBV enter the body of someone who is not infected.

Although anyone can get hepatitis B, certain life circumstances, jobs, and behaviors can increase your risk.

Learn more about specific risk factors for hepatitis B.


The best way to prevent hepatitis B is by getting vaccinated. You need to get all shots in the series to be fully protected.

CDC recommends the following groups get vaccinated against hepatitis B:

Learn more about preventing hepatitis B.

Get vaccinated‎

Vaccination is the best way to prevent hepatitis B. Learn more about recommendations and options for vaccination.

Screening, testing, and diagnosis

CDC recommends all adults get screened for hepatitis B at least once in their lifetime through a blood test. There are also some people who should be tested more often, including:

  • All pregnant people during each pregnancy.
  • Infants born to pregnant people with HBV infection.
  • People with ongoing risk for exposures.

Learn more about the types of tests used to diagnosis hepatitis B.

Are you a health care provider?‎

For clinicians looking to learn more about testing options for viral hepatitis, see the clinical testing guidelines.

Treatment and recovery

If you are diagnosed with acute or chronic hepatitis B, find a doctor who specializes in infectious, digestive, or liver diseases. They will need to do regular tests to monitor how your liver is working.

For people with acute hepatitis B and experiencing mild symptoms, health care providers usually recommend rest, adequate nutrition, and fluids. There are no medications for acute hepatitis B. There are some medications for chronic hepatitis B; they aren't a cure and are only helpful for some people with chronic hepatitis B. Learn more about treatment options for hepatitis B.

Myths and misconceptions

Hepatitis B is sometimes difficult to understand, especially how it spreads and how people recover. Here are a few misconceptions cleared up for you.

"If I don’t have symptoms, I’m not infected."

Many people with hepatitis B do not have any symptoms.

"If I don’t have symptoms, I can’t spread the virus to others."

You can still spread HBV to others even if you don’t have any symptoms.

"If I’ve been infected with HBV in the past, I can get it again."

Most people infected with hepatitis B who do not clear the virus within 6 months are diagnosed with chronic hepatitis B and remain infected. They cannot be infected again.

Some people — including people infected during childhood — can be infected for life if they never "clear" the virus from their bodies. These people are considered to have chronic hepatitis B and are at risk for severe liver disease.

"Hepatitis B can spread through saliva."

Although HBV can be found in saliva, it is not spread through kissing or sharing utensils. It is also not spread through sneezing, coughing, hugging, breastfeeding, or food or water.

What to expect long-term

If you have chronic hepatitis B, it's important to find a doctor who understands the disease and can regularly monitor your liver. Chronic hepatitis B can cause serious health problems, so having someone in your corner is critical.

If you've recently been diagnosed with hepatitis B, be sure to:

  • Get vaccinated against hepatitis A and tested for hepatitis C.
  • Consider testing for hepatitis D and human immunodeficiency virus (HIV).
  • Limit alcohol consumption.
  • Follow a healthy diet and stay physically active.
  • Check with a doctor before taking any prescription pills, nutritional or herbal supplements, or over-the-counter medications, as these can potentially damage the liver.

What CDC is doing

To end the public health threat of viral hepatitis, CDC works with health care providers, health departments, and community-based organizations to improve access to viral hepatitis prevention, testing, treatment, and care services in the United States.

In 2022, CDC updated hepatitis B vaccination recommendations to encourage and promote universal hepatitis B vaccination in all adults ages 19–59 and adults over 60 with risk factors for hepatitis B.

In 2023, CDC updated hepatitis B screening and testing recommendations to encourage and promote universal hepatitis B screening and testing in all persons 18 and older at least once in their lifetime.


For more resources, visit hepatitis B patient resources.