The Center for Disease Control and Prevention, commonly referred to as the CDC, advises that the best way to lower your chances of getting the flu is to get an annual flu shot. Complications and allergic reaction to flu shot vaccinations are considered rare and “worth the risk” for some people, particularly elderly people who live in nursing home situations.
Allergic reaction to flu shot vaccinations can be caused by any of the ingredients in the shot, but most often occur in people who are allergic to eggs. The shot contains dead influenza viruses that were grown in chicken eggs. It is believed, at least by the CDC, that most flu shot complications occur in people who have an allergy to chicken eggs.
The CDC advises that the signs of allergic reaction to flu shot vaccinations can include breathing problems, hoarseness or wheezing, hives, paleness, weakness, accelerated heartbeat, or dizziness and if they occur, it will be within the first few hours following the flu shot. Complications, other than the common side effects (redness or swelling at the injection site, low grade fever and body aches), should be reported to a doctor right away and the doctor should file a “Vaccine Adverse Event Reporting System” form. A severe allergic reaction to flu shot vaccinations can be life threatening and anyone who has had an allergic reaction to flu shot vaccinations in the past should consult a doctor before taking the annual flu shot.
Those people who are allergic to mercury or thimerosal may have an allergic reaction to flu shot vaccinations. Thimerosal is used in the manufacturing process of all flu vaccines and is used as a preservative in most. While the CDC states that there is “no convincing evidence” that thimerosal can cause severe flu shot complications, many doctors and researchers believe that mercury presence in flu shots can lead to autism and Alzheimer’s. The evidence concerning the link between mercury in flu shots and autism was convincing enough for New York state to ban vaccines containing thimerosal that are intended for use in pregnant women and children. But, even those flu shots which are labeled preservative free still contain trace amounts of mercury. It is generally not believed that these trace amounts can cause flu shot complications.
One of the flu shot complications that occurs rarely is a condition called Guillain-Barre syndrome. It is not considered an allergic reaction to flu shot vaccinations, but it may be associated with them. Guillain-Barre syndrome symptoms include fever and muscle weakness and sometimes results in paralysis and permanent nerve damage. The CDC advises that anyone who has had Guillain-Barre syndrome in the past, regardless of whether it was linked to flu shot complications, should consult their doctor before taking the annual vaccine.
Because severe allergic reaction to flu shot vaccinations are rare, the CDC believes that the benefits associated with the vaccine outweigh the risks associated with possible flu shot complications. The vaccine is considered to be 70-90% effective in preventing influenza in healthy persons under 65, 30-70% effective in preventing hospitalization due to influenza in elderly persons living outside of nursing homes, 50-60% effective in preventing hospitalization from influenza in elderly nursing home residents and 80% effective in preventing death from influenza in elderly nursing home residents.