Hepatitis A

Prevention

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.⁶

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.⁷ 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:⁸
  • 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.⁹

If you find out that you need the vaccine but you will be traveling in less than 4 weeks, you should receive the first shot in the vaccination series. One shot provides 90% protection from the disease and reduces the severity of disease. If you want to be extremely careful, you can receive the first shot in the vaccination series and a shot of immune globulin (IG). This will ensure that you are protected against HAV. You can receive the second shot of hepatitis A vaccine 6 to 18 months (depending on the recommendations of the vaccine's manufacturer) after the first shot.

Other factors to consider regarding the HAV vaccine:

• Two shots of vaccine are needed to protect you best, so try to get your first shot at least 6 months before you go to a foreign country where hepatitis A is common.
• Routine vaccination of hospital workers, food handlers, and child care center workers and attendees does not occur at this time since their chance of infection generally is no greater than that of the wider community. But some child care centers have workers get the shot because it works so well to prevent the disease. Plus there is very low chance of side effects from the vaccine. If outbreaks of HAV infection do occur in those settings, people who were exposed to the virus should receive a shot of immune globulin (IG).⁴
• If you have had close personal contact with someone who has hepatitis A, you should get the hepatitis A vaccine or a shot of IG as soon as possible. If you get the vaccine or IG within 2 weeks of being exposed to HAV, you probably will not develop symptoms of HAV infection.⁵ For more information, see the Medications section of this topic.
• The hepatitis A vaccine will also provide some protection against infection if you are already exposed to the virus.¹⁰

How to prevent HAV infection

• Get vaccinated against hepatitis A if your travel plans, job, medical condition, or lifestyle puts you at risk of exposure to the hepatitis A virus (HAV). For more information, see the What Increases Your Risk section of this topic.
• Develop good hygiene habits.
  • Make sure you and all members of your household always wash your hands thoroughly with soap and hot water after using the toilet and before preparing or eating food.
  • Wash dishes in hot, soapy water or in a dishwasher.
  • Discourage children from putting objects in their mouths, especially when sharing toys with other children.
  • Don't eat or drink anything that you think may have been prepared in unclean conditions.
• Protect yourself before you travel and while you're on your trip. If you plan to travel to a part of the world where sanitation is poor or where hepatitis A is a known problem, see your health professional about receiving the hepatitis A vaccine, immune globulin (IG), or the combination hepatitis A and B vaccine. Always drink bottled water or boil water before drinking it. Avoid tap water or well water or beverages containing ice cubes. And do not eat raw foods (such as unpeeled fruits or vegetables).
• Do not eat uncooked or undercooked shellfish. If shellfish are living in water that has been contaminated with stool containing the hepatitis A virus, the shellfish may carry the virus.

Child care workers should receive frequent instruction on preventing the spread of hepatitis A. Even though children infected with HAV may have few or no symptoms, they can spread the infection to others, including child care workers and other adults who may develop more serious symptoms. To prevent the spread of HAV, child care workers should:

• Wear plastic (not latex because of the risk of allergic reaction) disposable gloves when changing diapers.
• Wash their hands and wear a fresh pair of gloves before changing another child's diapers.
• Clean the diaper-changing surface after each changing.
• Talk to their health professionals about whether they should receive the HAV vaccine.

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Author:	Debby Golonka, MPH	Last Updated: November 16, 2006
Medical Review:	Kathleen Romito, MD - Family Medicine W. Thomas London, MD - Hepatology
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