Hepatitis A virus (HAV) is a single-stranded RNA picornavirus. It is the most common cause of acute viral hepatitis and is particularly common among children and young adults. HAV spreads primarily by fecal-oral contact and thus may occur in areas of poor hygiene. Waterborne and food-borne epidemics occur, especially in developing countries.
Symptoms and Signs
In children 6 years old, 70% of hepatitis A infections are asymptomatic, and in children with symptoms, jaundice is rare. In contrast, most older children and adults have typical manifestations of viral hepatitis, including anorexia, malaise, fever, nausea, and vomiting; jaundice occurs in over 70%. Manifestations typically resolve after about 2 months, but in some patients, symptoms continue or recur for up to 6 months. Recovery from acute hepatitis A is usually complete.
The hepatitis A vaccine is recommended for all children beginning at age 1 year, with a 2nd dose 6 to 18 months after the first.
Preexposure HAV vaccination should be provided for:
- Travelers to countries with high or intermediate HAV endemicity
- Diagnostic laboratory workers
- People with chronic liver disorders (including chronic hepatitis C) because they have an increased risk of developing fulminant
hepatitis due to HAV
- People who receive clotting factor concentrates
- People who anticipate close contact with an international adoptee during the first 60 days after arrival from a country with high
or intermediate HAV endemicity