Hepatitis A virus


Hepatitis A is a virus that causes an acute inflammation of the liver and is the most common form of all viral hepatitis. Hepatitis A is encountered frequently in the most disadvantaged geographical regions. Improvements in hygiene and sanitation have led to a reduction in the circulation of the virus, but not to its complete disappearance.

Symptoms of hepatitis A

  • Hepatitis A is often asymptomatic in young children, and more severe in adults. After an incubation period of 15 to 50 days, the onset of the disease is marked by a sensation of generalized malaise including, fever, headache, muscle soreness, fatigue, and gastrointestinal disorders. It is often accompanied by jaundice, particularly in adults.
  • The condition may be long-lasting, with an acute phase of approximately one month and a convalescence phase of up to six months.
  • No specific treatment is available.

Epidemiology and vaccination against hepatitis A

  • Hepatitis A is a strictly human disease. Transmission occurs through the fecal-oral route, from person to person, or by ingestion of contaminated food or drinking water.
  • Approximately 1.4 million cases are reported each year.
  • Hepatitis A is most common in urban areas but the incidence rates differ according to geographical regions and socio-economic levels.
  • Hepatitis A vaccines are available.


Hepatitis A vaccines. WHO fact sheet N°328 Revised May 2008

Koff R.S. Clinical Manifestations and Diagnosis of Hepatitis-A Virus Infection. Vaccine 1992; 10 (suppl):S15-S17.

Hadler SC. Global impact of hepatitis A virus infection: changing patterns. In Hollinger FB, Lemon SM, Margolis HS, eds Viral hepatitis and liver disease. Baltimore: Williams and Wilkins 1991;14-20