Vaccine is a weakened or killed form of a virus injected in the body that acts as an antigen, which helps body to build antibodies against it, so that the body is ready to fight off when there is infection with the same virus in future. Thus, hepatitis A vaccine helps prevent hepatitis A virus that can be a serious disease, if not fatal, but can require hospitalization in about 40% cases. Hepatitis A virus is spread through oral-fecal route, but can also be spread through contaminated water and ice, by having close personal relationship with an infected person such as living with the person or having sex with them. It can also be spread through contaminated foods such as fruits, vegetables, shellfish and uncooked food.
Who Should and Should Not Get Hepatitis A Vaccine?
Hepatitis A vaccine is given to all infants greater than 12 months of age, between 12 to 23 months of age. It is also given to people traveling to developing countries (such as parts of Africa, Asia, Central and South America and East Europe) where there is increased chances of food borne infection and contamination due to less sanitary habits; homosexual men; illicit drug users whether injectable or non-injectable; people with blood clotting disorders; people with chronic liver disease; people with close personal relationship or contact with hepatitis A infected person such as an international adoptee from a country where hepatitis A is common; people who work with HAV infected primates or with hepatitis A virus in laboratories. It can also be given to any individual who wants protection from hepatitis A infection.
Hepatitis A vaccine should not be given to people who have had severe allergic reaction to the vaccine in the past, people who have known allergies to any constituent of hepatitis A vaccine and people with moderate to severe acute illness. Hepatitis A vaccine is generally considered safe in pregnant women.
What Are The Side Effects of Hepatitis A Vaccine?
Hepatitis A vaccine is administered as a two-dose shot. The second dose is given after 6 months of the first shot, within 6-12 months from the first shot. Hepatitis A vaccine is administered in the upper arm. It should be administered when one is at a risk of acquiring the infection or start one month prior to traveling.
Generally, hepatitis A vaccine is considered safe, but there may be mild side effects to it, just like any other vaccine or medication. The side effects are usually mild and subside within two days of onset after 3-5 days of the injection. The most common side effect is soreness in the arm that occurs in one out of two adult and one out of every five children. Other less common side effects include low-grade fever, headache, loss of appetite and tiredness. In some rare cases, the patient may present with severe generalized allergic reaction to the vaccine. The severe allergic reaction, if happens, occurs within few minutes to few hours of the injection. The symptoms of severe reaction include high fever, difficulty breathing, hoarse voice or wheezing, hives, paleness of skin, weakness, dizziness, rapid heart rate and/or behavior changes. If these symptoms occur then one must contact doctor immediately.
Hepatitis A vaccine has been proved very effective and all individuals after receiving the vaccine get immune to hepatitis A. 94% people get immune to the infection after receiving one shot, but it is imperative to receive the full two dose of the vaccine. After the advent of hepatitis A vaccine in 1995, the disease rate has declined to about 95% in the United States.
There are also combination vaccines for both hepatitis A and hepatitis B available for adults. However, these have different schedules of dosing and one should inquire with their health care professional before getting that done. Twinrix is usually preferred when a person is traveling to parts of countries where there is increased rate of transmission for both the diseases.
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