What Is Hepatitis B?

Hepatitis B is a liver infection caused by the hepatitis B virus (HBV). In some people, HBV stays in the body, causing long-lasting disease and long-term liver problems.

How Do People Get Hepatitis B?

Most commonly, HBV spreads:

• through sexual activity with an HBV-infected person
• through shared contaminated needles or syringes for injecting drugs
• from HBV-infected mothers to their newborn babies

Who Is at Risk for Hepatitis B?

In the United States, the most common way people get infected with HBV is through unprotected sex with someone who has the disease. People who share needles also are at risk because the needles often aren't sterilized.

What Is Chronic Hepatitis B?

Doctors refer to hepatitis B infections as either acute or chronic:

• An acute HBV infection is a short-term illness that clears within 6 months of when a person is exposed to the virus.
• A person who still has HBV after 6 months is said to have a chronic hepatitis B infection. This is a long-term illness, meaning the virus stays in the body and causes lifelong illness. An estimated 850,000 to more than 2 million people in the U.S. have chronic HBV.

The younger someone is when infected, the greater the chances for chronic hepatitis B. 

What Are the Signs & Symptoms of HBV Infection?

HBV can cause a wide range of symptoms, from a mild illness and general feeling of being unwell to more serious chronic liver disease that can lead to liver cancer.

Someone with hepatitis B may have symptoms similar to those caused by other viral infections, like the flu. The person might:

• be extra tired
• feel like throwing up or actually throw up
• not feel like eating
• have a mild fever

HBV also can cause darker than usual pee, jaundice (when the skin and whites of the eyes look yellow), and belly pain.

People exposed to hepatitis B may start to have symptoms from 1 to 6 months later. Symptoms can last for weeks to months.

In some people, hepatitis B causes few or no symptoms. But even someone who doesn't have any symptoms can still spread the disease to others.

What Problems Can Hepatitis B Cause?

Hepatitis B (also called serum hepatitis) is a serious infection. It can lead to cirrhosis (permanent scarring) of the liver, liver failure, or liver cancer, which can cause severe illness and even death.

If a pregnant woman has the hepatitis B virus, her baby has a very high chance of having it unless the baby gets a special immune injection and the first dose of hepatitis B vaccine at birth.

Sometimes, HBV doesn't cause symptoms until a person has had the infection for a while. At that stage, the person already might have more serious problems, such as liver damage.

How Is Hepatitis B Diagnosed?

If you think you may have hepatitis B or you might have been exposed to the virus through sex or drug use, see your doctor or gynecologist to get tested. The blood test also can tell whether someone has an acute infection or a chronic infection. Let the doctor know the best way to reach you confidentially with test results.

How Is Hepatitis B Treated?

There's no cure for HBV. Doctors will advise someone with a hepatitis B infection on how to manage symptoms — like getting plenty of rest or drinking fluids. A person who is too sick to eat or drink will need treatment in a hospital.

In most cases, teens who get hepatitis B recover and may develop a natural immunity to future hepatitis B infections. Most feel better within 6 months. Health care providers will keep a close eye on patients who develop chronic hepatitis B.

What Happens After a Hepatitis B Infection?

Some people carry the virus in their bodies and are contagious for the rest of their lives. They should not drink alcohol, and should check with their doctor before taking any medicines (prescription, over the counter, or supplements) to make sure these won't cause more liver damage.

Anyone who has ever tested positive for hepatitis B cannot be a blood donor.

Can Hepatitis B Be Prevented?

Yes. Newborn babies in the United States now routinely get the hepatitis B vaccine as a series of three shots over a 6-month period. There's been a big drop in the number of cases of hepatitis B over the past 25 years thanks to immunization.

Doctors also recommend "catch-up" vaccination for all kids and teens younger than 19 years old who didn't get the vaccine as babies or didn't get all three doses. Anyone who is at risk for hepatitis B (including health care and public safety workers, people with chronic liver disease, people who inject drugs, and others) also should be vaccinated.

Some people may need to be revaccinated even if they got the vaccine as a baby. This includes people:

• whose mothers carry the hepatitis B virus in their blood
• who need hemodialysis
• who have a weak immune system

To prevent the spread of hepatitis B through infected blood and other body fluids, teens should:

• abstain from sex (oral, vaginal, or anal)
• if sexually active, always use latex condoms when having sex (oral, vaginal, or anal)
• avoid contact with an infected person's blood
• not use intravenous drugs or share needles or other drug tools
• not share things like toothbrushes or razors
• research tattoo and piercing places carefully to be sure they don't reuse needles without properly sterilizing them