Community outbreaks contribute to more than half of all hepatitis A infections. Transmission between children and then to their adult caregivers is the primary way this infection is passed within a community. An infected person sheds the virus in the stool. Even though the virus has been found in human saliva, confirmed transmission through saliva has never been proven.

Contaminated foods and direct personal contact by infected people with poor hygiene make up the majority of the means of transmission, even though it is possible to be transmitted by blood transfusion and also by sexual intercourse. Eating raw meat or undercooked meat increases the risk of catching hepatitis A. Thorough cooking in high temperature should kill any hepatitis A virus in contaminated foods.

A person infected with hepatitis A starts spreading the virus two weeks before he starts feeling sick. Even though this is the most contagious period during the infection, the person has no idea that he is shedding the virus and spreading it to others because he does not feel sick at all. In addition, anyone who gets sick from him would not feel any ill effects until a month later.

This long incubation period for the infection makes quarantine of infected individuals tremendously difficult. Children tend to stay infectious for much longer periods of time than adults. Some children continue to spread the virus more than two months after they apparently recover from an acute hepatitis A infection.