Epidemiology of Hepatitis A: Past and Current Trends

Hepatitis A virus is a common infectious etiology of acute hepatitis worldwide. It was not until World War II (1973) when hepatitis A virus was first identified by an American virologist, Stephen Mark Feinstone. The virus is most commonly transmitted through contaminated food, water, or sexual contact (oral-anal sex). The discovery of hepatitis A virus vaccine is considered a milestone in the history of acute viral hepatitis. Hepatitis A occurs worldwide and frequent outbreaks have been reported over the years. Major geographic differences have existed in endemicity of the disease depending primarily upon hygiene and sanitation practices. Some countries have experienced shifting of endemicity due to improvement of environmental hygiene, swelled International travel and national recommendations for hepatitis A vaccination. The age of acquiring hepatitis A virus is also shifting toward adolescents and adults. This has led to a more symptomatic disease, since hepatitis A infection among children is usually asymptomatic; this is known as the paradox of Hepatitis A epidemiology.