What is hepatitis B?

Short Answer

Hepatitis B is a contagious disease that affects the liver. It is one of several hepatitis diseases (for example, hepatitis A and hepatitis C) caused by different germs, but similar in that they all affect the liver. There are two types of infection, acute (lasting a few weeks) and chronic (lasting a lifetime). Symptoms of acute hepatitis B include fever, fatigue, loss of appetite, nausea, vomiting, jaundice (yellow of the eyes or skin), joint pain, and abdominal pain. Chronic hepatitis B can cause symptoms similar to the acute version, but can lead to extremely serious and sometimes deadly liver damage. Ninety-five percent of children who get three to four doses of the hepatitis B vaccine will be protected from hepatitis B.





Symptoms & Incubation
Infants and young children usually show no symptoms. In about seven out of 10 older children and adults, short-term hepatitis B causes the following:

  • Loss of appetite
  • Fever
  • Tiredness
  • Pain in muscles, joints, and stomach
  • Nausea, diarrhea, and vomiting
  • Dark urine
  • Yellow skin and eyes

Symptoms of short-term illness usually appear three or four months after infection. When first infected, a person can develop an acute infection, which can range in severity from a very mild illness with few or no symptoms to a serious condition requiring hospitalization. Acute hepatitis B refers to the first six months after someone is infected by the hepatitis B virus. Some people are able to fight the infection and clear the virus. For others, the infection remains for life and is known as chronic or lifelong hepatitis B.

Some people with chronic hepatitis B have ongoing symptoms similar to acute hepatitis B, but most individuals with chronic hepatitis B remain symptom free for as long as 20 or 30 years. About 15%–25% of people with chronic hepatitis B develop serious liver conditions, such as cirrhosis (scarring of the liver) or liver cancer. Even as the liver becomes diseased, some people still do not have symptoms, although certain blood tests for liver function might begin to show some abnormalities.

People with lifelong hepatitis B usually don’t have symptoms, but the virus causes liver damage over time. For these people, there is no cure, but treatment can help prevent serious problems. Each year, 3,000 to 5,000 people in the U.S. die from liver damage or liver cancer caused by hepatitis B.

Of the more than a million people in the United States living with lifelong hepatitis B, most got the virus as a child. When infants and young children are infected with hepatitis B, they have a 90% chance of developing a lifelong, chronic infection. A quarter of these children will have serious liver disease as an adult, including cancer. Children and adults with lifelong hepatitis B can pass the virus on to other people.

Hepatitis B spreads through blood or other body fluids that contain small amounts of blood of an infected person. People can spread the virus even when they have no symptoms.

Babies and children can get hepatitis B in the following ways:

  • At birth from their infected mother
  • From bites from an infected person
  • By touching open cuts or sores of an infected person
  • Through sharing toothbrushes or other personal items used by an infected person
  • From food that was chewed (for a baby) by an infected person
  • From ear- or body-piercing needles that were not cleaned well

The virus can live on objects for seven days or more. Even if you don’t see any blood, there could be virus on an object.

The hepatitis B vaccine is a copy of only one small part of the virus, and the vaccine cannot cause the infection.

Children need three to four doses of the hepatitis B vaccine (depending on the brand of vaccine used) at the following ages for best protection:

  • The first dose at birth (within 12 hours if the mother has hepatitis B infection);
  • A second dose at 1 through 3 months; and
  • A third dose at 6 through 18 months of age.

Some children may need a fourth dose. Talk to your child’s doctor to find out how many shots your child needs. Any older child who did not get the vaccine as a baby should get it as soon as possible.

All babies should get the first shot of hepatitis B vaccine before they leave the hospital. This shot acts as a safety net, reducing the risk of getting the disease from moms or family members who may not know they are infected with hepatitis B. And when a mom has hepatitis B, in addition to the hepatitis B vaccine, the baby should also get a dose of hepatitis B immune globulin (HBIG) within the first 12 hours of life. HBIG is a medicine that gives a baby’s body a “boost” or extra help to fight the virus as soon as he or she is born. The HBIG shot is only given to babies of mothers who have hepatitis B.

Safety & Side Effects
The hepatitis B vaccine is very safe, and it is effective at preventing hepatitis B. Vaccines, like any medicine, can have side effects. Most people who get the hepatitis B vaccine will have no side effects at all. Those that do occur are very mild, such as a low fever (less than 101 degrees Fahrenheit) or a sore arm from the shot. No serious side effects are known to be caused by the hepatitis B vaccine.

Since the Vaccine Was Introduced…
Routine hepatitis B vaccination was recommended for some U.S. adults and children beginning in 1982, and for all children in 1991. Since 1990, new hepatitis B infections among children and adolescents have dropped by more than 95% – and by 75% in other age groups.