Hepatitis A

Hepatitis A is a highly contagious liver disease that results from infection with the hepatitis A virus. It can range in severity from a mild illness lasting a few weeks to a severe illness lasting several months. Sometimes hepatitis A can cause liver failure and death. Although this outcome is rare, it occurs more commonly in people older than 50 and people with other liver diseases.

Hepatitis A usually spreads when a person unknowingly ingests undetected amounts of virus in the feces (stool) from an infected person. This can happen through:

  • Ingestion of contaminated food or water
  • Close person-to-person contact with an infected person
  • Sexual contact with an infected person


Hepatitis A can be prevented with a safe and effective vaccine. Individuals at greatest risk for acquiring hepatitis A infection include those who:

  • Travel to or live in countries where hepatitis A is common
  • Are family members or caregivers of a recent adoptee from countries where hepatitis A is common
  • Use recreational drugs (injection or non-injection)
  • Experience unstable housing or homelessness
  • Are currently or were recently incarcerated
  • Are men who have sex with men (MSM)
  • Live with or have direct contact someone who has hepatitis A
  • Engage in sexual contact with someone infected with hepatitis A

Individuals at greatest risk of developing serious complications from hepatitis A infection are those who:

  • Have chronic liver disease, including cirrhosis, hepatitis B, or hepatitis C
  • Persons with human immunodeficiency virus infection
  • Are adults aged >40 years

Adults at risk for or for severe disease from hepatitis A virus infection should be offered the hepatitis A vaccine to prevent infection. In addition, all children aged 12-23 months and all children and adolescents aged 2-18 years who have not previously received hepatitis A vaccine should be vaccinated.

Pre-vaccination serologic testing is not required to administer hepatitis A vaccine. Vaccinations should not be postponed if vaccination history cannot be obtained or records are unavailable.

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