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Hepatitis A Immunization

By , BSc

Hepatitis A is a liver condition caused by the highly contagious hepatitis A virus. It can infect anyone and the usual route of transmission is fecal-to-oral, either through contact with food or water contaminated with infected feces or through contact with an infected person. Cooked food is safe to eat, so long as the temperature it is cooked at is high enough to kill the virus. However, food may still be contaminated if an infected individual has handled it.

This virus is common in areas with poor water supplies, sanitation and personal and food hygiene standards such as Africa, Central and South America and parts of the Middle and Far East.

Once a person is infected, no symptoms develop during the incubation period, which is two to six weeks. I ndividuals may be unaware they are carrying the infection. S ymptoms that can last for one week or more include :

  1. Fatigue
  2. Body aches and pains
  3. Loss of appetite
  4. Fever
  5. Nausea and vomiting
  6. Diarrhea
  7. Stomach ache

Following initial symptoms, j aundice develops, which causes the whites of the eyes to turn yellow and in more severe cases, turns the skin yellow and the urine dark. Stools may also become pale. Jaundice occurs as a result of the liver failing to work properly and break down the waste product bilirubin, which then accumulates in the body. In the majority of cases, people recover within a few weeks and unlike other forms of hepatitis, there is no long-term liver damage.

Hepatitis A Vaccination

Vaccination is t he most effective way of preventing hepatitis A\ . The vaccine is recommended for all children aged one year or more, for people traveling to countries where the virus is common and for people who have a high risk of transmitting the infection.

The vaccine is administered in two shots, given six months apart. A combination vaccine for hepatitis A and hepatitis B is also available. Anyone 18 or older can receive it. For this vaccine, three shots are given over the course of six months or one shot is given over the course of one month and then followed with a booster injection at 12 months.

Children

The first dose of vaccine should be administered somewhere between the ages of 12 and 23 months, but children who have not been vaccinated by 2 years can still be vaccinated at subsequent visits. A shot called immune globulin (IG), which provides protection for up to 3 months, can be given to infants younger than 12 months.

Travelers

Any person one year or older who is intending to travel to developing countries where there is high or intermediate risk of transmission should receive the hepatitis A vaccine. Travelers should begin the series as soon as the trip is confirmed. An IG shot can be given in addition to the vaccine for individuals who are intending to travel for more than two months. The shot must be repeated if the travel period is longer than five months. People who are allergic to the vaccine or choose not to be vaccinated may receive the IG shot instead.

Other groups

Individuals at high risk of infection should also receive a series of vaccinations and these include the following:

  1. Men who have sex with men
  2. Users of certain illegal injection and non-injection drugs
  3. People with an occupational risk such as those who work in hepatitis A research
  4. People with chronic liver conditions
  5. People with clotting factor deficiencies

People who should not be vaccinated or who should wait to be vaccinated include the following:

  1. Those who have a severe allergic reaction to the hepatitis A vaccine or any other vaccine component previously should not be vaccinated again.
  2. Anyone who is ill at the time they are due to receive the shot should wait until they recover, unless the illness is only mild, in which case they can usually be safely vaccinated.
  3. The safety of vaccination among pregnant women has not yet been determined, although the risk of any harm to either the mother or baby is thought to be very low. The risks associated with vaccination should be carefully weighed up against the risk of infection.

Reviewed by Catherine Shaffer, M.Sc.

Sources

Further Reading

Last Updated: Nov 20, 2016

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