Hepatitis A is a virus that is spread through the fecal oral route, and then replicates in the liver. The virus is present in blood and feces 10 to 12 days after infection and excretion may continue for up to three weeks after falling ill. Symptoms are usually extremely mild or nonexistent in children less than six years of age. In older children and adults, clinical features include fever, fatigue, a decreased appetite, nausea, abdominal pain, dark urine, and jaundice. Symptoms usually last less than two months, but 10 to 15% of people can have signs and symptoms lasting up to six months. Prior to vaccination, Hepatitis A caused about 100 deaths per year in the United States mostly in older people. Hepatitis A has a high cost due to hospitalizations and decreased days of work. In 1989, the total cost of hepatitis A was more than $200 million.
Transmission is usually fecal-oral, drug use, from person-to-person or from contaminated food or water.
Hepatitis A vaccine is recommended at 12 months of age and then again 6 to 18 months following the first dose. Adverse reactions include pain at the injection site due largely to the needle. Contraindications include severe allergic reaction to a component or moderate to severe illness.