Introduction: The Hepatitis A virus (formerly known as Enterovirus 72) has a long history and still has a large impact on human populations in the modern world. Since the time of the ancient Greek physician Hippocrates, the hepatitis A virus (HAV) was known to cause jaundice. In the 8th century it was realized that jaundice was caused by an infectious agent. Later in history, in 1885, scientists discovered that hepatitis could spread through blood transfusions. It is now known that the virus is transmitted mainly via the fecal-oral route, resulting from the contamination of food and water by fecal material and from direct contact with infected individuals. Initially, another jaundice agent, hepatitis B virus, was isolated in 1973 by Robert H. Purcell. This followed the isolation of HAV from marmoset liver explant cultures in 1979 (5). The understanding of HAV had begun after World War II due to its enormous impact on soldiers and civilians in wartime conditions favored by contamination. HAV was first visualized under an electron microscope at the National Institutes of Health in the stool of volunteers who had had an HAV infection (1, 2). The hepatitis A virus causes acute viral hepatitis, one of the most common infectious diseases resulting from inflammation. of liver. HAV is not the only infectious agent that causes acute viral hepatitis. Several viruses, called hepatitis A, B, C, D and E cause inflammation of the liver. Different hepatitis viruses belong to different virus families. HAV is a small, cubically symmetric, 27 nm, single-stranded RNA virus with positive (+) strand polarity and is classified as a member of the picorna virus family. It has also been classified as the main virus of the hepatovirus genus... middle of paper... hygiene may be more common. In the general population, the seroprevalence rate of anti-HAV antibodies ranges from 15% to 100% in different countries around the world. In developing countries, most infections occur by 5 years of age and seroprevalence rates can reach 100% (7). Northern Europe has the lowest seroprevalence rate in the world. The decrease in seroprevalence is problematic as it indicates that the majority of individuals in the defined population are susceptible to HAV infection which can lead to an epidemic outbreak. In 1988, an epidemic occurred in Shanghai due to the ingestion of inadequately cooked bivalve molluscs from polluted wastewater, which caused the infection of approximately 300,000 people (1). In regions where the majority of individuals are susceptible to HAV infection, routine vaccination is suggested to prevent HAV epidemic outbreaks(7).