Hepatitis A and B

Viral Hepatitis (A and B) · Hep A · Hep B

The Facts

Hepatitis is the medical term for inflammation of the liver. Hepatitis may be acute (lasting only for the short term, after which a person recovers) or chronic (lasting for the long term, usually more than 6 months).

There are many causes of hepatitis, including viruses, alcoholism, and medications. Viral hepatitis is now a major cause of chronic hepatitis in North America. There are five hepatitis viruses: A, B, C, D, and E. There are also other viruses that can cause liver inflammation, like Epstein-Barr virus and cytomegalovirus, but these viruses are not called hepatitis viruses.

Hepatitis A and B (HAV and HBV) are common causes of liver inflammation in North America. In 2007 around 25,000 new cases of HAV and 43,000 new cases of HAB were diagnosed in the United States. Since many infected people have no symptoms, however, we can assume the true rate of infection is higher than this. Many experts believe that up to one-third of the population has been infected with HAV at some point.

Among people born in North America, hepatitis A is most common in children and young adults, while hepatitis B is most common in adults between the ages of 20 and 40 years.


Hepatitis A is mainly transmitted through the fecal-oral route. That means infected people shed viruses in their feces. If they don't observe proper hygiene, the virus can end up on their hands. It's then spread by food they've handled, or sometimes by touching other people who then bite their nails, handle their food, and so on.

The virus can survive on tabletops, doorknobs, telephones, or other such places for 2 or 3 hours at room temperature. Although less common, you can also get hepatitis A from direct contact such as kissing, through sexual contact, or by sharing needles. Though many people who are infected have no symptoms, they can still pass on the disease.

People at high risk for hepatitis A include:

  • anyone who lives with an infected person
  • children and workers in daycare centers
  • homosexual men
  • intravenous drug users
  • people with many sexual partners
  • people who live in permanent institutions like prisons or homes for the developmentally disabled, or those who are in the armed forces
  • those who have recently been in the Middle East, South America, Eastern Europe, Central America, Africa, or Southeast Asia – areas with greater likelihood of exposure to contaminated food or water

Hepatitis B is spread by blood and body fluids. The main routes of transmission are through sexual contact, sharing needles, tattooing and body piercing, and childbirth (when the baby is likely to pick up the virus from the mother through the birth canal). Hepatitis B has an additional complication – some infected people become lifelong carriers, whether they have symptoms or not. Many infected people are asymptomatic (without symptoms) but can pass on the virus.

People at high risk for hepatitis B include:

  • intravenous drug users
  • people with many sexual partners
  • homosexual men
  • people who live in prisons
  • those who have recently been in the Middle East, South America, Eastern Europe, Central America, Africa, or Southeast Asia
  • people who receive hemodialysis
  • health care workers
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The contents of this health site are for informational purposes only. Always seek the advice of your physician or other qualified healthcare provider regarding any questions you may have about a medical condition.

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