Hepatitis A Vaccine

The hepatitis A vaccine can protect against the virus for at least 20 years. It consists of two injections, given several months apart. Children can get the vaccine after 1 year of age (it is recommended between 12 and 23 months of age). People who should get the hepatitis A vaccine include travelers to developing countries with high rates of hepatitis A and users of illegal drugs.

The hepatitis A vaccine can protect against the virus for at least 20 years. It consists of two injections, given several months apart. Children can get the vaccine after 1 year of age (it is recommended between 12 and 23 months of age). People who should get the hepatitis A vaccine include travelers to developing countries with high rates of hepatitis A and users of illegal drugs.

An Introduction to the Hepatitis A Vaccine

A vaccine is a drug that you take when you are healthy that keeps you from getting sick. Vaccines teach your body to attack certain viruses, like the hepatitis A virus.

The hepatitis A vaccine is given through a shot. Children can get the vaccine after they are 1 year old. It is recommended that children receive the vaccine between 12 and 23 months of age. The second shot should follow 6 to 12 months later. Adults get two shots over a period of 6 to 12 months.

Candidates for the Hepatitis A Vaccine

The following people should get the hepatitis A vaccine as a routine vaccination: 

• Children living in areas with high incidence rates of hepatitis A (above the national average) check with your health department to see if this applies to your area

• Travelers to developing countries with high rates of hepatitis A, including Mexico

• Men who have sex with men

• Users of illegal drugs

• People who work with hepatitis A virus in research settings

• People who work with infected non-human primates

• Recipients of clotting factor concentrates

• People with chronic liver disease (because of the risk of fulminant hepatitis A).

Who Should Either Avoid or Wait to Get the Hepatitis A Vaccine?

You should not get the hepatitis A vaccine if: 

• You have had a severe (life-threatening) allergic reaction to a previous dose of the vaccine.

• You have had a severe (life-threatening) allergy to any vaccine component. Tell your healthcare provider if you have any severe allergies. Some types of hepatitis A vaccine contain alum and 2-phenoxyethanol.

If you are moderately or severely ill at the time you are scheduled to receive the shot, you should wait until you have recovered before getting the hepatitis A vaccine. However, ask your doctor or nurse. People with a mild illness can usually get the vaccine.

Be sure to tell your healthcare provider if you are pregnant before getting the vaccine. The safety of hepatitis A vaccine for pregnant women has not been determined; however, there is no evidence that it is harmful to either pregnant women or their unborn babies. The risk, if any, is thought to be very low.

How Long Does the Hepatitis A Vaccine Last?

If you are vaccinated and develop antibodies, you will be protected against hepatitis A for at least 20 years. If you are unsure about whether or not you have been vaccinated, ask your healthcare provider to check if you have antibodies in your blood to protect you against the virus. Vaccination is the best form of hepatitis A prevention.

Hepatitis A Vaccine and Recent Exposure

If you were recently exposed to the hepatitis A virus, you may still get temporary protection with a shot of immunoglobulin (IG), which is a mixture of antibodies. It may protect you from the virus for three to five months. It works best if given within two weeks after exposure. At the same time, you should begin the hepatitis A vaccine shots. 

If you are traveling within a month to places that have high rates of hepatitis A infection, and if you have not already received the vaccine, a shot of IG may protect you.

Side Effects of the Hepatitis A Vaccine

The hepatitis A vaccine is made from an inactive virus and is quite safe. In general, there are few side effects. The most common side effect is soreness at or around the injection site. Other side effects include:                                                      

• Mild headache

• Loss of appetite (among children)

• Feeling tired.

These side effects usually begin three to five days after the vaccination and may last one to two days.

However, like any medicine, the hepatitis A vaccine may cause serious problems, such as an allergic reaction, which may appear within a few minutes or hours after the shot. This occurs only rarely, but if you believe you are having a reaction to the vaccine, you should call your doctor or nurse right away. Some warning signs of a serious allergic reaction include the following: 

• High fever

• Changes in behavior

• Difficulty breathing

• Hoarse voice or wheezing

• Hives

• Pale skin

• Weakness or dizziness

• A fast heartbeat.

Hepatitis A Vaccine Schedule

Doses and schedules for the hepatitis A vaccine are listed in the following table.