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Hepatitis A
(HAV, Hep A)

Hepatitis A Facts

  • Hepatitis is a general term that means inflammation (irritation and swelling) of the liver. Inflammation of the liver can result from infection, exposure to alcohol, certain medications, chemicals, poisons, or from a disorder of the immune system.
  • Hepatitis A refers to liver inflammation caused by infection with the hepatitis A virus (HAV). HAV is one of several viruses that can cause hepatitis, and is one of the three most common hepatitis viruses in the United States.
  • The other two common types are hepatitis B and hepatitis C; however, there are other named types such as D, E, F, and G, and more types may be discovered in the future. Moreover, these infections are somewhat different from hepatitis A, and from each other.
  • Unlike hepatitis B and hepatitis C, hepatitis A does not cause chronic (ongoing, long-term) disease. Although the liver becomes inflamed and swollen, it heals completely in most people without any long-term damage. Once a person contracts hepatitis A, they develop lifelong immunity, and rarely contract the disease again.
  • Because of the way it is spread, the hepatitis A virus tends to occur in epidemics and outbreaks. As many as 1 in 3 adults (>age 19) in the United States have antibodies to HAV, meaning they have been exposed to the virus, but most do not become ill.
  • In 2011, researchers report no significant change in seroprevalence (the frequency of people in a population that have particular antibodies, usually reactive against a disease-producing organism in their blood serum) of HAV antibodies in adults before or after the HAV vaccine became available (see reference 3).
  • The number of cases of hepatitis A in the United States varies among different communities, and has been reduced by the introduction of the hepatitis A vaccine. The rate of infection (number of infections per 100,000 people) has declined since 1999.
  • Vaccination at age one year may cause the rate and yearly case numbers of HAV to decline.

Hepatitis A Causes

The cause of hepatitis A is hepatitis A virus (HAV) that is transmitted person to person by contaminated foods, water or other drinks (including ice), blood, stool, and direct contact. The virus is a Picornavirus that contains single-stranded RNA as its genome covered by a protein shell. The virus enters through the epithelium in the mouth or gut and migrates to the liver over a period of about two to six weeks. Symptoms (jaundice and other symptoms, see below) then begin to develop as the virus replicates in the liver cells (hepatocytes and Kupffer cells, also termed liver macrophages). HAV reproduces itself by utilizing the liver cell's ribosomes for viral replication; however this interferes with normal liver cell function. If large numbers of liver cells are infected with HAV, the person will develop symptoms. The viruses are secreted into the GI tract by the bile fluid made in the liver. The majority of people infected recover with no lasting damage to the liver.

Hepatitis A Virus (HAV) Courtesy of the CDC

Picture of the Hepatitis A Virus (HAV)
Medically Reviewed by a Doctor on 11/21/2017

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Patient Comments & Reviews

The eMedicineHealth doctors ask about Hepatitis A (HAV, Hep A):

Hepatitis A - Symptoms

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Hepatitis A Vaccine

What is the hepatitis A vaccine, and who should get one?

There are vaccines that work to prevent infection with hepatitis A virus.

  • The vaccines, Havrix and VAQTA, contain no live virus and are very safe. No serious adverse effects have been reported. Some people have some soreness at the injection site for a few days.
  • The vaccines are given in a series of 2 shots. The second is given 6-18 months after the first. The shots can be given at the same time as other vaccines.
  • Your protection starts about 2-4 weeks after the first shot. The second dose is necessary to ensure long-term protection.
  • The vaccines are thought to protect from infection for at least 20 years.
  • The vaccines must be given before exposure to the virus. They do not work after exposure.

Not everyone needs to have the hepatitis A vaccines. However, the vaccines are recommended for the following groups:

  • People who are likely to be exposed to HAV at work - The only group of workers shown to be at higher risk than the general population is people who work in research laboratories where HAV is stored and handled. Routine vaccination is not recommended for health care workers, food service workers, daycare personnel, and sewage and waste-water workers.
  • Individuals visiting developing countries (it must be given at least 4 weeks before the trip)
  • Men who have sex with men
  • People who use illegal drugs - This group has higher-than-average rates of HAV infection.
  • People who are likely to become seriously ill if they are infected with HAV - This includes people with impaired immune systems or chronic liver disease.
  • People with blood-clotting disorders who receive clotting factors

Read What Your Physician is Reading on Medscape

Hepatitis A »

One of the more common causes of acute hepatitis is hepatitis A virus (HAV).

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