The hepatitis A vaccine is the most effective means of preventing hepatitis A virus (HAV) infection. The vaccine provides 94% to 100% protection if you receive both of the shots in the vaccination series.⁵

Immunization with the hepatitis A vaccine is recommended for:

• All children beginning at 1 year of age. Two separate doses are given at least 6 months apart.⁶ The U.S. Centers for Disease Control and Prevention made this recommendation in early 2006. Many young children and adolescents have not had the hepatitis A vaccine.
• Children and adolescents who have not had the hepatitis A vaccine and who are in the following situations:⁷
  • A community outbreak of the disease has recently occurred.
  • They live in a state or community that has set up routine vaccination because the disease occurs there more often than in other areas.
• People whose travel, job, medical condition, or lifestyle puts them at risk of exposure to the virus. This includes:
  • People who are planning a trip to a foreign country where sanitary conditions are poor and hepatitis A is common.
  • People who use illegal drugs.
  • Men who have sex with men.
  • People who work with monkeys that are infected with the virus and those who work with the virus in a research setting.
  • People who have long-term (chronic) liver disease.
  • People who are awaiting or have had a liver transplant.
  • People with hemophilia or related blood-clotting disorders.

A combination vaccine (Twinrix) that prevents hepatitis A and hepatitis B is available for people 18 and older.

Considerations regarding the hepatitis A vaccine

Adults who are planning a trip to foreign countries where hepatitis A is common may want to be tested for HAV antibodies (anti-HAV test) before beginning a hepatitis A vaccination program. If you already have HAV antibodies in your blood, you are protected against infection, and you do not need to be vaccinated.

Consider the following before going through with anti-HAV testing before vaccination:

• Vaccination may be less expensive than anti-HAV testing. Testing costs include the cost of a doctor visit and lab tests. If the tests show that you need to be vaccinated, you will have to pay for the full vaccination series (two shots given at different times), including the expense of additional office visits.
• You can receive hepatitis A vaccine even if you already have HAV antibodies in your blood, and no harm will result.
• The hepatitis A vaccine is not fully effective until 4 weeks after the shot. But the vaccine does give some protection after 2 weeks.³ If you are going to be tested for anti-HAV, make sure to do so well in advance of your trip. People older than 60 might want to get the vaccine earlier than 4 weeks before departure, because evidence suggests that the immune response develops more slowly in older people.⁸