The U.S. Food and Drug Administration (FDA) approved five injectible vaccines (flu shots) for seasonal influenza during the 2009 to 2010 flu season. While most people will benefit from the flu shot, it is contraindicated in people with certain kinds of allergies. Prior to receiving any vaccine, always share any history of allergies or hypersensitivities with your healthcare provider.
Hypersensitivity to Eggs
The influenza vaccine virus is grown in fertilized chicken eggs. All five brands of flu shot approved in 2009-2010 reported the presence of approximately 1 microgram (0.000001 g) of ovalbumin (egg white protein) in each dose. According to the manufacturers’ product literature, people with severe allergies to any component of the egg should not be vaccinated.
Hypersensitivity to Antibiotics
Antibiotics are frequently used in the flu shot manufacturing process, in order to prevent bacterial contamination of the chicken eggs. Antibiotics used in the production of 2009-2010 flu shots include neomycin, polymyxin and kanamicin. Two kinds of flu shots, Fluzone and Flulaval, do not use antibiotics.
Hypersensitivity to "Any Other Component"
Each of the manufacturers lists the blanket warning for people with known hypersensitivity to “any other component” of the vaccine. Each manufacturer disclosed potential trace contaminants of their vaccine. Examples include formaldehyde (100 micrograms or less), sodium deoxycholate (50 micrograms or less), betapropionolactone (0.5 micrograms or less), gelatin and other ingredients. Patients with allergies should always review the manufacturer’s product insert prior to receiving any specific brand of flu shot. Fluarix is the only brand that uses natural rubber latex.
Previous Life-Threatening Reaction to Influenza Vaccine
People who have previously had a life-threatening allergic reaction after receiving the flu shot or the intranasal vaccine, FluMist, should not be vaccinated again. Examples of life-threatening allergic reactions include anaphylaxis and angioedema (swelling under the skin). According to the American College of Allergy, Asthma and Immunology, anaphylaxis may result in death due to cardiac arrest. According to Medline Plus, angioedema may progress to anaphylaxis or it may cause death on its own due to airway blockage.