Hepatitis A

What is Hepatitis A?

The Hepatitis A virus (HAV) is a member of the picornavirus family, which invades liver cells and causes inflammation. Considered the least serious of all hepatitis viruses, HAV does not cause chronic liver disease. This disease usually lasts no longer than six months. Cirrhosis and its complications, as well as liver cancer, do not occur from contracting HAV. Fortunately, it is the most common vaccine-preventable disease in the entire world, and those who get HAV develop immunity from ever contracting it again.

How is it Transmitted?

The virus is transmitted by the fecal-oral route. This means that transmission occurs when the virus embedded in the feces of an infected person enters the digestive tract of another person. The virus enters the mouth through infected unwashed hands and/or contaminated food or water, passes from the stomach to the small intestine, and then gains entry into the liver where replication of the virus occurs. After the virus multiplies in the liver, it passes through the bile ducts to the intestines, where it mixes with stool and is eliminated from the body.

Transmission occurs primarily through person-to-person contact and ingestion of contaminated food and water. Unsanitary living conditions and poor personal hygiene standards increase the risk of becoming infected with Hepatitis A. Uncooked food that is prepared by an HAV-infected person who did not properly wash his/her hands after defecating can transmit the virus. Raw or incompletely cooked shellfish such as oysters, clams and mussels have a particularly high incidence of transmitting the virus because they live in bodies of water that may be polluted with it.

Who Is At Risk?

Those at risk for contracting HAV:

  • People traveling to developing countries (tourist, military personnel, Peace Corps workers and missionaries, etc.) due to the likelihood of poor sanitary conditions and unsafe drinking water
  • Individuals that engage in oral/anal intercourse
  • Intravenous drug users
  • Sewage workers
  • Food industry workers
  • Employees or children in a day care setting
  • Employees and patients in institutions (nursing homes and rehabilitation centers)
  • A family member of someone with a recent Hepatitis A infection


The development of symptoms is related to the age of the person. Approximately 90 percent of Hepatitis A infected children younger than 5 years old are asymptomatic. Thus, children in diapers can unknowingly pass the virus to their parents, caregivers and other children in their environment.

Older adults may have symptoms, but the degree of symptoms can vary greatly. Some people without symptoms are surprised to learn that they were exposed to the virus. Others may have nonspecific symptoms such as fatigue, chills, loss of appetite and low-grade fever. More severe symptoms include a sudden fever, abdominal pain, diarrhea, nausea, vomiting, dark urine and jaundice. Within a week of becoming jaundiced, most people experience malaise and weight loss. A small percentage of people with Hepatitis A become so ill that they require hospitalization.

Symptoms and signs usually last one to two months. In any scenario, by six months all symptoms and signs of will resolve. Once a person has had Hepatitis A, they develop immunity to the disease and cannot get it again.

How is it Diagnosed?

A blood test known as the Hepatitis A serology is needed to positively diagnose the virus. The standard series includes both the immunoglobulin M (IgM) antibody to HAV and the immunoglobulin G (IgG) antibody to HAV. A host of other liver function tests may be given routinely whenever liver disease is suspected.


No specific medications are used to treat Hepatitis A. Usually treatment decisions are based on the symptoms experienced. Bed rest and decreased physical activity are recommended for those experiencing fatigue. Increased intake of water is advised in most cases to prevent dehydration. All alcohol should be avoided as this may provoke a relapse of the disease. About 99 percent of patients recover without medical intervention.

Residual Effects

According to Hepatitis Foundation International, Hepatitis A will clear up on its own in a few weeks or months with no serious after effects. Once recovered, an individual is then immune for life to HAV through the presence of the IgG antibody. About 1 in 100 sufferers may experience a sudden and severe (i.e., “fulminant”) infection.

Also, a small number of people with Hepatitis A will continue to experience signs and symptoms of infection for several weeks longer than usual. For these people, symptoms may go away and then reappear over several weeks. Though the symptoms occur over a longer period of time, this form of infection is not more serious than an infection that causes the usual symptoms.

In rare cases, it can cause acute liver failure, which is a loss of liver function that occurs suddenly. People with the highest risk of this complication include those with chronic liver diseases and older adults. Acute liver failure requires hospitalization for monitoring and treatment. In some cases, people with acute liver failure may require a liver transplant.

This information is intended for educational purposes only and should not be used in any other manner. This information is not intended to substitute for informed medical advice. You should not use this information to diagnose or treat a health problem or disease without consulting with a qualified health care provider.

Suggested Articles

About the Author

Stephen Holt, MD, PhD, FACP

Stephen Holt, M.D. is a Distinguished Professor of Medicine NYCPM (Emerite) and a medical practitioner in New York State. He has published many peer-review papers in medicine and he is a best-selling author with more than twenty books in national and international distribution. He has received many awards for teaching and research. Dr. Holt is a frequent lecturer at scientific meetings and healthcare facilities throughout the world. He is a best selling author and the founder of the Holt Institute of Medicine.

Centers for Disease Control and Prevention. "Hepatitis A Information for the Public" http://www.cdc.gov/hepatitis/A/index.htm Retrieved February 9, 2011

Dolan, Mathew, The Hepatitis Handbook. North Atlantic Books, 1999.

Hepatitis Foundation International. "The ABC's of Hepatitis" http://www.hepfi.org/living/liv_abc.html Retrieved February 9, 2011.

Mayo Clinic. "Hepatitis A" http://www.mayoclinic.com/health/hepatitis-a/DS00397 Retrieved February 9, 2011.

Palmer, MD, Melissa. Dr. Melissa Palmer’s Guide to Hepatitis & Liver Disease. New York: Avery Trade, 2004.

Get our 3 FREE Liver Health Booklets close popup