What is a Hepatitis a Vaccine?

Hepatitis A is a viral disease that affects the liver. People with hepatitis A often experience flu-like symptoms. They may need to be hospitalized, and in severe cases, the disease may lead to death. The hepatitis A vaccine prevents this disease by encouraging the body to build a defense against the virus. In response to the injection of dead, or inactive, viral material, the body manufactures antibodies, a type of protein, to destroy the virus.

General guidelines for the hepatitis A vaccine recommend that all persons who are at least one year old should be vaccinated. It is also recommended that those who are at a higher risk of contracting the virus be vaccinated, if they weren’t already vaccinated as children. Those who live in, or travel to, certain countries — such as Africa, parts of Asia, and Mexico — have a higher risk of contracting it. People who live in other communities with an increased incidence of hepatitis A should also receive the hepatitis A vaccine.

Other risk factors that call for vaccination include people who use street drugs and men who have sexual intercourse with other men. Patients with chronic liver disease should also receive the hepatitis A vaccine, as well as those who receive medications that affect blood-clotting. Certain jobs also lead to a higher risk of infection, such as people who work in laboratories with the virus itself, or those who work with lab animals who are infected with it.

Not all people should receive the hepatitis A vaccine. Patients who have had a severe allergic reaction to a previous dose of the vaccine should not receive a booster shot. The risk to an unborn child is unknown, so pregnant women should consult with their doctors. Patients who are ill should wait to receive the vaccine until they have recovered.

The hepatitis A vaccine is usually given in two separate shots, for maximum protection. A first dose is administered to a person who is at least one year old. The second dose may be given no sooner than six months following the first, but typically no more than 12 months later. Adults and older children who receive the hepatitis A vaccine will generally have the injection in the upper arm, while toddlers will receive it in a thigh muscle.

There is a possibility for mild side effects with this vaccination. Some patients experience soreness, swelling, or redness at the injection site. Others may have a headache, fatigue, and nausea. Some patients may find they have a temporary loss of appetite.

Serious risks due to this vaccination are rare. It is not possible to contract the hepatitis A virus from the vaccine. Some people may experience an allergic reaction, which may include symptoms of dizziness, rapid heart rate, and wheezing. Other signs of an allergic reaction are difficulty breathing, hives, and weakness. Patients who experience this reaction, typically within a few minutes or hours of receiving the shot, should get immediate medical help.