Disease & Vaccine Information

What is Hepatitis A?

Updated February 03, 2023

hepatitis a virus

Hepatitis A is viral disease of the liver caused by the hepatitis A virus (HAV). The hepatitis A virus is a nonenveloped RNA virus and considered to be a picornavirus. Humans are the only natural host of this virus.  The hepatitis A virus is very stable and can remain present for several months in most environments. The virus, however, can be killed by high temperatures (temperatures greater than 85C/185F), or by solutions such as chlorine, or formalin.   

Hepatitis A is contracted orally and typically acquired by coming into contact with human fecal waste, generally through the consumption of contaminated food and/or water.  Source of contamination may include raw shellfish, fruits and vegetables and ice. 

Hepatitis A replicates in the liver and can be found in the blood stream within 10 to 12 days following exposure. The virus is excreted by the biliary system into the feces of a contaminated individual.  An infected individual can spread hepatitis A to others for one to two weeks prior to becoming symptomatic.    Excretion of the virus may persist longer in children than adults, however, by the third week of the illness, most infected individuals no longer excrete the virus in their feces. 

It generally takes an average of four weeks (range of two to seven weeks) following exposure to hepatitis A for symptoms to develop. Symptoms often occur suddenly and include fatigue, abdominal and/or joint pain, loss of appetite, fever, nausea, jaundice, dark urine, clay-colored bowel movements, and diarrhea. Young children are often asymptomatic and show no clinical signs of infection.  Most infected individuals recover fully within two months, however, approximately 10 to 15 percent of infected individuals can have lingering symptoms for up to six months. 

Hepatitis A infection does not result in chronic liver disease  and persons who recover from the illness develop lifelong immunity. 

IMPORTANT NOTE: NVIC encourages you to become fully informed about Hepatitis A and the Hepatitis A vaccine by reading all sections in the Table of Contents, which contain many links and resources such as the manufacturer product information inserts, and to speak with one or more trusted health care professionals before making a vaccination decision for yourself or your child. This information is for educational purposes only and is not intended as medical advice.



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