Hepatitis A is a serious viral liver disease. An affected person may get jaundice, abdominal pain and diarrhea, or a “flu-like” syndrome with generalized muscle aches, headache, fever/chills, and fatigue. Though suffering may be considerable, the illness is generally self-limiting and resolves in about six weeks, but it can also be fatal in rare cases. The virus can be easily passed by close personal contact, such as between family members, and is also frequently transmitted via contaminated water and food.
Those at risk include individuals living with someone diagnosed with Hepatitis A, staying in an area in which in which there is an outbreak of Hepatitis A, or simply visiting in areas known to have a high incidence of Hepatitis A (such as Africa, Central America, South America, Mexico, and parts of Asia and Eastern Europe).
The primary reason why an adult should get the Hepatitis A vaccine is generally for planned travel to areas in which they would potentially be exposed to the virus, either by contact with infected individuals or contaminated water. This vaccine is also given to children over one year of age as part of their routine vaccination program. Occasionally, there will be outbreaks of Hepatitis A in communities that do not normally have a high incidence of Hepatitis A, and in these instances a community vaccination program is put in place to vaccinate anyone who has not previously had the vaccine. The vaccine is also recommended for those with chronic liver disease, and also for those with blood disorders requiring transfusions of clotting factors, and for men who have sex with men. Hepatitis A can be transmitted from non-human primates, such as chimpanzees, to people so the vaccine is also recommended for those who work in research labs with Hepatitis A infected primates.
For travelers, the vaccine should be given at least one month before departure, preferably three to six months prior. This is to allow for the development of full immunity.
The Hepatitis A vaccine produces immunity to the disease that is thought to last at least 20 years, and may be life-long.
The current vaccines are well tolerated and no serious adverse events have been statistically linked to their use. Hepatitis A vaccine may be administered with all other vaccines included in the Expanded Program on Immunization and with vaccines commonly given for travel.
Anyone who has had a previous allergic reaction to the vaccine or any of its components should not receive the Hepatitis A vaccine. It is important to discuss any allergies with a health care professional prior to getting the vaccine. Someone with a serious illness should probably wait to get the vaccine. Those with mild unrelated illness may generally go ahead and get the vaccine. The safety of the vaccine in pregnant women has not been firmly established, though the risk is thought to be low and must be balanced against the risk of contracting the disease.
The Hepatitis A vaccine is generally very well tolerated. Some soreness often occurs at the site of injection, and some patients will develop headache and tiredness. The only serious problems associated with the vaccine occur as a result of an allergic reaction. This, like any allergic reaction can develop and progress quickly and can be serious to the point of being life-threatening. Signs of a serious allergic reaction can include difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heartbeat or dizziness. If such a reaction were to occur, it would be within a few minutes to a few hours after the shot. If these symptoms begin to develop, do not wait; call 911 or have someone drive you to the closest emergency department immediately.