Search the site

Hepatitis A


What is Hepatitis A?

Hepatitis A is a contagious liver infection caused by the hepatitis A virus (HAV).  In the USA, hepatitis A infections have declined by 90% since the hepatitis A vaccine first became available in 1995. Still, there are cases of hepatitis A reported to the San Francisco Department of Public Health every year among San Francisco residents. Hepatitis A is still common in Latin America, Africa, the Middle East, Asia, and eastern Europe.


How do People Get Hepatitis A?

Hepatitis A virus is found in the stool (feces) of people with HAV infection. It enters the body through the mouth after someone handles something contaminated with HAV, or eats or drinks something contaminated with HAV.


People usually get hepatitis A by having close contact with a person who is infected, from food or drinks prepared by someone who is infected, or by eating shellfish harvested from sewage-contaminated water.  After the virus enters the body, there is an incubation period lasting 2 to 7 weeks until illness begins.


Who is at Risk for Infection?

Anyone who is not immune to hepatitis A can get hepatitis A infection. Food-borne outbreaks occur sporadically throughout the USA. Certain groups of people do have a higher risk of developing HAV infection:


  • Persons living in the same household with an infected person
  • Sex partner of an infected person
  • Persons traveling to countries where hepatitis A is common
  • Men who have sex with men
  • People who use injection drugs
  • Children in day care
  • People who eat raw or undercooked shellfish


How is Hepatitis A Infection Prevented?


  • The hepatitis A vaccine offers excellent protection against HAV. The vaccine is safe and highly effective. Vaccination consists of 2 doses of vaccine (shots) spaced 6-12 months apart. Protection starts 1-2 weeks after the first dose of vaccine, and lasts for 20 years to life after 2 doses.
  • The American Academy of Pediatrics recommends that all children should receive hepatitis A vaccine at 1 year of age (2007 AAP Statement).
  • The CDC recommends hepatitis A vaccine for all persons traveling to countries where HAV is common (CDC Yellow Book).


Natural Immunity

  • People who have hepatitis A infection become immune to HAV for the rest of their lives once they recover. They cannot get hepatitis A twice.
  • The blood test for immunity to hepatitis A is called the "Hepatitis A Total Antibody test." People who have had hepatitis A and those who have received hepatitis A vaccine show positive antibodies to hepatitis A on this test for the rest of their life.

Healthy Habits

  • Good personal hygiene and proper sanitation help prevent the spread of the HAV virus. Always wash your hands with soap and water after using the bathroom, changing a diaper, and before preparing, serving, or eating food.
  • People who have hepatitis A should not be preparing or serving food, or caring for the elderly or for young children, until at least 2 weeks have passed since the first sign of hepatitis A illness.
  • Boiling or cooking food and drinks for at least 1 minute to 185°F (85°C) inactivates HAV. Foods and drinks heated to this temperature and for this length of time do not transmit HAV infection unless they become contaminated after heating. Travelers can lower their risk of hepatitis A (and other food-borne illnesses) in developing countries by drinking only water that has been boiled or chemically purified, by eating only foods that have been properly heated, and by avoiding fruits or vegetables that are not peeled or prepared by the traveler personally.
  • Adequate chlorination of water as recommended in the United States does inactivate HAV.

After Exposure to HAV

  • Hepatitis A infection can be prevented by getting vaccine or immune globulin soon after coming into contact with the virus.
  • Persons who have recently been exposed to HAV should get immune globulin or vaccine as soon as possible, but not more than 2 weeks after the last exposure.
  • If you have recently been exposed to hepatitis A, you should immediately contact your doctor or call the Communicable Disease Control Unit at (415) 554-2830.


What are the Symptoms of Hepatitis A?

Children who become infected with hepatitis A before age 6 usually have no symptoms (70%) or mild illness, and if they do become ill, they usually get better in under 2 months.  Adults and older children who become infected with hepatitis A can have no symptoms or very mild illness (30%), but most develop jaundice and other symptoms (70%). Mild illness can resolve in 1-2 weeks, but more severe illness can last for months.  Common symptoms of HAV infection include:


  • Jaundice
  • Dark-colored urine, light-colored stools
  • Fatigue
  • Abdominal pain
  • Loss of appetite
  • Nausea
  • Diarrhea
  • Fever


The blood test for hepatitis A infection is called the "Hepatitis A IgM Antibody test." People who have hepatitis A infection right now will show positive IgM antibodies on this test. While most people heal completely from hepatitis A infection, a small number, usually those with pre-existing liver disease, suffer major liver damage which can result in death (0.3-1.3%).


If you think you have hepatitis A, you should immediately contact your doctor.


Additional Information

© Copyright 1998 - 2017, Department of Public Health, City and County of San Francisco Privacy Policy|Sitemap|Contact Us