Exposure to the hepatitis A virus (HAV) can lead to an acute liver infection that is typically mild and self-resolving. The symptoms and duration of illness can vary widely, with many individuals showing no symptoms at all. The most commonly associated symptoms of HAV infection include fever and jaundice.


Throughout history, hepatitis infections have been a persistent challenge for humanity. The earliest records of contagious jaundice can be traced back to ancient China. According to the CDC, the first descriptions of hepatitis—referred to as epidemic jaundice—are generally attributed to Hippocrates. Reports of jaundice outbreaks, likely linked to hepatitis A, occurred in the 17th and 18th centuries, particularly during military campaigns.

Hepatitis A was first epidemiologically differentiated from hepatitis B, which has a longer incubation period, in the 1940s. The development of serologic tests enabled definitive diagnosis of hepatitis B. By the 1970s, the identification of strains of the virus and the creation of serologic tests allowed for the distinction between hepatitis A and other non-B hepatitis types.


Until 2004, HAV was the most frequently reported type of hepatitis in the United States. Before the advent of vaccines, the primary preventive measures against HAV infections consisted of hygienic practices and passive protection with immune globulin (IG). Hepatitis A vaccines were licensed for use in 1995 and 1999. These vaccines offer long-lasting protection against HAV infection.
Hepatitis A is the only widely vaccine-preventable foodborne disease in the United States.

This virus is one of five human hepatitis viruses that primarily target the liver and result in human illness. Unlike hepatitis B and C, hepatitis A does not lead to chronic hepatitis or cirrhosis, both of which can be life-threatening conditions. However, infection with the hepatitis A virus can still result in acute liver failure and death.

Hepatitis A is a communicable disease often transmitted from person to person. This person-to-person transmission occurs through the fecal-oral route, while other forms of exposure are typically linked to contaminated food or water. Foodborne outbreaks are generally associated with contamination during food preparation by a food handler who is infected with HAV. Notably, these food handlers often do not exhibit any symptoms, as the peak period of infectivity—when the highest concentration of the virus is present in an infected individual’s stool—occurs up to two weeks before symptoms appear.

Fresh produce contaminated during the stages of cultivation, harvesting, processing, and distribution has also been identified as a source of hepatitis A. In 1997, frozen strawberries were implicated in an outbreak of hepatitis A across five states. Six years later, in 2003, fresh green onions were linked to an HAV outbreak traced back to food consumed at a Pennsylvania restaurant. Other fruits and vegetables, including blueberries and lettuce, have also been identified as potential sources of hepatitis A outbreaks.