En español

Disease information 

Virus or bacteria

Hepatitis B is caused by hepatitis B virus, a virus that attacks the liver causing severe liver disease.

How it spreads

Hepatitis B spreads through exposure to an infected person’s blood by activities that include, but are not limited to:

• Tattooing
• Intravenous drug use
• Sex with an infected individual
• Sharing washcloths, toothbrushes or razors that contain even minute quantities of blood from an infected person

Although it occurs rarely, young children can also come in contact with the virus in blood:

• From an infected adult in the home or an infected caregiver
• On items that are shared and can be put in the mouth, like toys, pacifiers or utensils
• From bites that break the skin

About half of the people in the U.S. who are chronically infected with hepatitis B virus do not know they have the infection, so they may not take sufficient steps to prevent spreading it to others.

If 10 susceptible people live in a house with one person who is infected with hepatitis B, 4 of 10 people will likely become infected.

Symptoms

Stage 1

• Fever
• Vomiting
• Nausea
• Aversion to food
• Headache
• Abdominal pain
• Rash
• Dark-colored urine
   

Stage 2

• Jaundice
• Discoloration of feces
• Enlarged and tender liver

Young children are less likely to have symptoms of hepatitis B infection, but they are more likely to develop chronic infections. About 9 of every 10 infants exposed to this virus will develop chronic, life-shortening infections.

Typical disease timeline

The first stage of hepatitis B infection can last up to 10 days; the second stage can last up to 3 weeks. Some people will become chronically infected and may not realize they are infected until they develop liver cancer or liver failure.

Possible complications

• Severe liver damage
• Liver failure
• Liver cancer
• Death (About 5,000 people die every year)

Other things to know

• Hepatitis B is about 100 times more infectious than HIV.
• Hepatitis B only occurs in people.
• Hepatitis B virus can live on objects and cause infections if someone comes into contact with it for a week after being left on the object by an infected person.
• Before hepatitis B vaccine was recommended for all infants in the U.S., about 18,000 children less than 10 years of age were infected with hepatitis B each year.

Vaccine information

The hepatitis B vaccine is used to prevent hepatitis B.

Vaccine type

• Recombinant vaccines

Vaccine side effects

Common

• Redness or swelling at the injection site (1 to 4 of 100 adults)
• Pain or soreness at the injection site (3 to 9 of 100 children; 13 to 29 of 100 adults)
• Mild fever (Up to 6 of 100 children; 1 to 3 of 100 adults)
• Headache (Up to 20 of 100 children; 21 to 25 of 100 adults)
• Fatigue (Up to 20 of 100 children; 21 to 25 of 100 adults)
• Irritability (Up to 20 of 100 children; 11 to 17 of 100 adults)

Rare

• None

Very rare

• Severe allergic reaction (About 1-2 of 1 million recipients)

Reasons to get the hepatitis B vaccine

• Hepatitis B virus still infects about 100,000 people in the U.S. every year.
• Many people do not know they are infected with hepatitis B virus.
• The consequences of hepatitis B infection tend to be worse when people are infected at a young age.
• You can get hepatitis B from quantities of blood that cannot be seen with the naked eye. This means the virus can be spread through somewhat casual contact, like sharing washcloths, toothbrushes or razors.
• The hepatitis B vaccine is safe. 

Newborns should get a first dose of hepatitis B vaccine no more than 12 hours after birth. Cases of hepatitis B in children less than 19 years of age dramatically decreased since this approach to hepatitis B vaccination was started in 1991.

Adults up to 60 years of age should get the hepatitis B vaccine if they have not already been vaccinated. 

Those 60 years of age and older should get the vaccine if they are high risk or if they simply want to be protected against hepatitis B.