What is hepatitis A?

Short Answer

Hepatitis A is a serious liver disease caused by the hepatitis A virus, which is transmitted through contact with the stool  of an infected person. It is usually spread by close personal contact and sometimes by eating food or drinking water that has been contaminated. Symptoms don’t always appear, but when they do, the most common are fever, fatigue, loss of appetite, nausea, vomiting, joint pain, jaundice (yellowing of the skin or eyes), and abdominal pain. It is one of several hepatitis diseases (for example, hepatitis B and hepatitis C) caused by different germs, but similar in that they all affect the liver. Hepatitis A can be prevented through vaccination, which is 94% effective after two doses in children.



Symptoms & Incubation
Children under 6 years old usually have no symptoms. Older children and adults feel very sick and weak. Symptoms may include the following:

  • Fever
  • Loss of appetite
  • Tiredness
  • Stomach pain
  • Vomiting
  • Dark urine
  • Yellow skin and eyes

People feel sick two to six weeks after they get the hepatitis A virus. Most people with hepatitis A feel very sick for about two months, but some are sick for up to six months.


Ten to 15% of people who contract hepatitis A will experience a relapse of symptoms within six months of the initial infection. Hepatitis A can lead to liver failure, a rare but extremely serious complication that can be fatal. Liver failure is more of a risk in elderly people. About 100 people in the U.S. die each year from liver failure caused by hepatitis A.

Hepatitis A virus is found in the stool (feces) of a person who has the virus. It spreads when a person puts something in his or her mouth that has the hepatitis A virus on it. Even if the item looks clean, it can still be contaminated with the virus since the amount of infected stool on an item can be so tiny that it cannot be seen with the naked eye. The virus spreads when a person touches the infected item, then touches his or her mouth.

The virus spreads easily from one family member to another. People are most likely to spread hepatitis A virus in the two weeks before they feel sick. Sometimes the virus can get into food or water. If this happens, the virus can quickly spread to anyone who eats or drinks the af­fected food or water (this is uncommon in the United States).

The hepatitis A vaccine prevents hepatitis A disease. It is made from killed (inactivated) virus. The vaccine protects children by prepar­ing their bodies to fight the hepatitis A virus.

Safety & Side Effects
The hepatitis A vaccine is very safe, and it is effective at preventing hepa­titis A disease. Vaccines, like any medicine, can have side effects.

Mild side effects include:

  • soreness where the shot was given (about one out of two adults, and up to one out of six children)
  • headache (about one out of six adults and one out of 25 children)
  • loss of appetite (about one out of 12 children)
  • tiredness (about one out of 14 adults)

If these problems occur, they usually last one or two days. In very rare cases, a serious allergic reaction can take place within a few minutes to a few hours after the shot.

Children should get the hepatitis A vaccine at 12 through 23 months of age. The vaccine can be less effective if given before 12 months (1 year) of age. Those who do not get the vaccine by age 2  should get the shot at their next doctor visit.

The vaccine is given in two doses, at least six months apart. Children can get the hepatitis A vaccine at the same time as other vaccines.

Since the Vaccine Was Introduced…
Because of the use of hepatitis A vaccine, the number of cases of the disease in the U.S. has dropped. But about 20,000 people still get hepatitis A each year. A child who is not vaccinated is at risk for getting hepatitis A.