Hepatitis A is one of five known viruses that cause inflammation of the liver (the others are B, C, D, and E). The Centers for Disease Control and Prevention (CDC) estimate that a third of the U.S. population becomes infected during their lifetime. Most people recover from the hepatitis A virus within six months without any lasting health problems, however the disease can be more serious in adults.

How is hepatitis A transmitted?
Transmission is usually by drinking water or eating food that has been contaminated with fecal matter containing the virus. Unlike the hepatitis B and C viruses, the hepatitis A virus remains stable when liver cells secrete it into bile, which enters the digestive tract.

Fecal matter from an infected person has a high concentration of the virus, whereas saliva and other bodily fluids have a low concentration. The virus can survive in this contaminated fecal matter on a person's hand, for example, or on a surface for three to four hours at normal room temperatures. Thus, an eating utensil contaminated with the virus could be a way to transmit the infection to a person. Contaminated shellfish is a frequent source of infection. Direct contact with an infected person is another confirmed transmission route, as are kissing on the mouth and anal sex. Contamination of needles used for intravenous administration of drugs is a suspected route of transmission. In about 42% of the reported cases, it is not known how people were infected.

Who is at risk for hepatitis A?
The risk of being infected with the hepatitis A virus generally depends on the hygiene and sanitary conditions in an area. High-risk geographic areas are the Middle East, South America, Eastern Europe, Central America, Africa, Southeast Asia, Mexico and the Caribbean. Travelers to these areas are at risk even if they stay at exclusive hotels and resorts. There are also areas in the United States where poor sanitary conditions have resulted in an outbreak of hepatitis A.

Children at daycare centers spread the virus because of fecal-oral contamination through diaper changing. Outbreaks have been reported in the military and at institutions for the disabled.

Those using injectable drugs with contaminated needles have also been infected with the virus.

The CDC lists household or sexual contact, daycare attendance or employment, and international travel as the major known risk factors for the transmission of hepatitis A.

What are the symptoms for hepatitis A infection?
As with the other hepatitis viruses, a person infected with hepatitis A may not have any symptoms. Common symptoms resemble the flu. These include fatigue, nausea, vomiting, pain in the liver area, dark urine or light colored stools, and fever. Liver function tests are elevated, with many adults developing jaundice. Children under two rarely have symptoms. Most people recover within six months, but the experience can result in economic harship due to lost wages and associated medical care costs.

Can hepatitis A result in serious complications?
A small percentage of people infected with hepatitis A risk serious complications. These include people with alcoholic hepatitis, chronic hepatitis cirrhosis or the elderly over 60 years old. These patients may suffer liver failure after becoming infected with hepatitis A. It is estimated that hepatitis A is the primary cause of death for about 100 people each year. Patients with hepatitis A may show improvement in their symptoms and liver function tests only to suffer a relapse, usually after four weeks. A relapse can occur more than once and there is no way to predict who will suffer a recurrence of acute symptoms. In rare cases, jaundice lasts for two or more months. The average adult can miss up to five weeks of work due to the illness. It is rare for pregnant women who are infected with hepatitis A to suffer serious complications to themselves or their newborn children.

How is hepatitis A diagnosed?
Hepatitis A is diagnosed by a blood test that is positive for the antibody to the virus, which appears about four weeks after the infection. There are no false positives or negatives with this test. Liver function tests (serum alanine aminotransferase [ALT]) are elevated above normal, often to very high levels. Symptoms will normally appear during the first four weeks of infection.

How is hepatitis A treated?
There is no specific treatment for hepatitis A. Most patients are told to rest for one to four weeks after a diagnosis is made, to avoid intimate contact and to consume foods high in protein. People who have come into contact with the patient should be given temporary immunization with immune globulin, within two weeks of exposure.

What is the hepatitis A vaccine?
There are two approved vaccines available in the U.S. for protection against hepatitis A. The vaccine is made from inactive hepatitis A virus particles. The body reacts with the inactive virus to produce an antibody that protects against infection of the liver by the hepatitis A virus.

Clinical trials have shown that the vaccine is effective in preventing infection in about 95% of people who were exposed. There are generally no known side effects, except for soreness at the site of the injection. Less than 10% of those vaccinated become tired and nauseous. The hepatitis A vaccine is considered safe and effective.

Children between two and 18 should receive one initial dose of the vaccine and a booster between six and 12 months later. Adults should receive an initial dose and a booster six to 12 months later. It takes at least two weeks before protection is achieved. Current data show that protection lasts at least six years, but experts believe that protection may last ten years or longer when the series is completed.


The information contained in this sheet is provided for information only. This information does not constitute medical advice and it should not be relied upon as such. The American Liver Foundation (ALF) does not engage in the practice of medicine. ALF, under no circumstances, recommends particular treatments for specific individuals, and in all cases recommends that you consult your physician before pursuing any course of treatment.