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Hepatitis A

Infectious liver disease, spread primarily through the fecal-oral route, caused by the hepatitis A virus; now preventable by vaccine. Most people recover and the infection does not become chronic.

PubMed Health Glossary
(Source: NIH - National Institute of Diabetes and Digestive and Kidney Diseases and National Library of Medicine)

About Hepatitis A

Hepatitis A is spread primarily through food or water contaminated by feces from an infected person. Rarely, it spreads through contact with infected blood.

Who is at risk for hepatitis A?

People most likely to get hepatitis A are

  • international travelers, particularly those traveling to developing countries
  • people who live with or have sex with an infected person
  • people living in areas where children are not routinely vaccinated against hepatitis A, where outbreaks are more likely
  • day care children and employees, during outbreaks
  • men who have sex with men
  • users of illicit drugs

NIH - National Institute of Diabetes and Digestive and Kidney Diseases

What works? Research summarized

Evidence reviews

Hepatitis A immunisation in persons not previously exposed to hepatitis A

Hepatitis A is a common, contagious viral disease in many low‐income countries. It is estimated that world wide, around 1.5 million people are affected each year. The hepatitis A virus is limited to man and several species of non‐human primates. It is transmitted primarily by faecal‐oral spread from person to person, or through ingestion of contaminated food or water. Since 1995, hepatitis A vaccines have been used to prevent hepatitis A in people not yet exposed to the hepatitis A virus. Only three of the included trials were considered to be at low risk of bias; that is, free from overestimation of benefits and underestimation of harm due to systemic errors. In persons not previously exposed to hepatitis A infection, hepatitis A vaccination with inactivated or live attenuated hepatitis A vaccines had a clear effect on reducing the risk of developing clinically apparent hepatitis A. The review also found that hepatitis A vaccines significantly reduce the risk of lacking protective antibodies against hepatitis A. The inactivated vaccine appears to be relatively safe. There were insufficient data to draw any conclusions on production of protective antibodies and adverse events for live attenuated vaccines.

Immunoglobulins (human serum immune gamma globulins) seem effective for prevention of hepatitis A

Hepatitis A is a common, contagious viral disease in low‐income countries. Hepatitis A is transmitted primarily by faecal‐oral spread from person to person. Passive immunoprophylaxis for hepatitis A using immunoglobulin preparations were essential for prevention before development of specific hepatitis A vaccine (active immunisation). This review concludes that immunoglobulins seem effective for preventing hepatitis A in both children and adults. However, the evidence, on which the conclusion is based, is not strong as the included trials appear to have risk of bias and their number is insufficient. Because there is a potential risk of blood‐borne diseases from immunoglobulins preparations, such as human immunodeficiency virus, and because of the availability of hepatitis A vaccine, the use of immunoglobulins has become limited. However, their use is still required in some specific populations, such as persons with compromised immune function, children under one year of age, or persons who have not developed a full response to vaccine immunisation. Future clinical trials should address the benefit and harm of immunoglobulins in these populations.

Effect and safety of Yinzhihuang injection for icteric viral hepatitis: a systematic review

Bibliographic details: Chen J, Chen H Y, Liu Z C, Wu T X.  Effect and safety of Yinzhihuang injection for icteric viral hepatitis: a systematic review. Chinese Journal of Evidence-Based Medicine 2005; 5(6): 461-465

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Summaries for consumers

Hepatitis A immunisation in persons not previously exposed to hepatitis A

Hepatitis A is a common, contagious viral disease in many low‐income countries. It is estimated that world wide, around 1.5 million people are affected each year. The hepatitis A virus is limited to man and several species of non‐human primates. It is transmitted primarily by faecal‐oral spread from person to person, or through ingestion of contaminated food or water. Since 1995, hepatitis A vaccines have been used to prevent hepatitis A in people not yet exposed to the hepatitis A virus. Only three of the included trials were considered to be at low risk of bias; that is, free from overestimation of benefits and underestimation of harm due to systemic errors. In persons not previously exposed to hepatitis A infection, hepatitis A vaccination with inactivated or live attenuated hepatitis A vaccines had a clear effect on reducing the risk of developing clinically apparent hepatitis A. The review also found that hepatitis A vaccines significantly reduce the risk of lacking protective antibodies against hepatitis A. The inactivated vaccine appears to be relatively safe. There were insufficient data to draw any conclusions on production of protective antibodies and adverse events for live attenuated vaccines.

Immunoglobulins (human serum immune gamma globulins) seem effective for prevention of hepatitis A

Hepatitis A is a common, contagious viral disease in low‐income countries. Hepatitis A is transmitted primarily by faecal‐oral spread from person to person. Passive immunoprophylaxis for hepatitis A using immunoglobulin preparations were essential for prevention before development of specific hepatitis A vaccine (active immunisation). This review concludes that immunoglobulins seem effective for preventing hepatitis A in both children and adults. However, the evidence, on which the conclusion is based, is not strong as the included trials appear to have risk of bias and their number is insufficient. Because there is a potential risk of blood‐borne diseases from immunoglobulins preparations, such as human immunodeficiency virus, and because of the availability of hepatitis A vaccine, the use of immunoglobulins has become limited. However, their use is still required in some specific populations, such as persons with compromised immune function, children under one year of age, or persons who have not developed a full response to vaccine immunisation. Future clinical trials should address the benefit and harm of immunoglobulins in these populations.

Bile acids may improve liver biochemistry of patients with hepatitis B or C, but there is insufficient evidence about long‐term beneficial effects

Viral hepatitis causes significant morbidity and mortality. Based on this Cochrane systematic review, bile acids may decrease serum transaminase activities in patients with acute hepatitis B, chronic hepatitis B, or chronic hepatitis C. However, bile acids have no effects in eradicating viral markers. There is insufficient evidence either to support or to refute effects on the long‐term outcomes that include hepatocellular carcinoma, decompensated cirrhosis, and/or liver related mortality.

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More about Hepatitis A

Photo of a young adult

Also called: Hep A

See Also: Hepatitis

Other terms to know:
Feces, Jaundice

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