Seasonal flu vaccine has been widely recommended to people unless they are younger than six months of age, have a history of allergic reaction to flu shot, have a history of Guillain-Barre Syndrome, or a history of egg allergy.
But it's important to note that the egg-allergic person can get a flu shot if specific guidelines are followed under the guidance of an allergy specialist. A recent publication in the journal Annals of Allergy, Asthma and Immunology (Oct 2009 Vol. 103, No.4 Suppl) outlined steps for allergists to consider in the situation of an egg-allergic patient.
Recommendations for Adults and Children
Recommendations are for the child or adult to be tested (or re-tested) to egg. If the person has a positive skin test to egg, the flu vaccine is used to perform a prick skin test. An intradermal test (small injection under the top layer of skin, like a TB test, injected type) is done if the prick test to flu vaccine is negative. Both tests are read after about 15 minutes.
If the intradermal flu vaccine test is negative (and egg test positive) the shot is given in one dose, with the same flu vaccine used for testing. The patient is observed for 30 minutes after the injection to assure safe tolerance.
If either the intradermal test or prick test to the flu vaccine is positive, the flu shot may be given in five small doses that collectively add up to the dose recommended by package insert (.25 or .5 cc dose based on age). The protocol published in the Annals article gives a step by step account of how much vaccine to administer and the observation times in between and after the last dose. The protocol is for allergy specialists to follow.
The Risk of Allergic Reaction Is Still Present
Although the above approach minimizes the risk of having a severe allergic reaction to the flu vaccine, it does not eliminate risk. For this reason it is imperative that flu vaccination, in the setting of egg allergy or flu vaccine allergy, be done by an allergy specialist and in an environment which offers emergency resuscitation in case of anaphylaxis.
The H1N1 vaccine (swine flu) is also egg based and carries the same precautions as seasonal flu vaccine. The same protocol may be used in order to administer H1N1 to an egg allergic or seasonal flu allergic patient.
Unfortunately, allergists cannot test you to the seasonal flu or H1N1 vaccine with the intent of sending you out to the nearest vaccination center to safely get your vaccination. Why?
Let's suppose the results of the skin test to seasonal flu vaccine are negative. These results only apply to the seasonal flu vaccine material used for testing. The allergist uses the same lot of flu vaccine for testing, that he or she uses for vaccination (each flu vaccine bottle has a Lot #). If the patient were to get the flu vaccine somewhere else, the vaccine could possibly be part of a different lot and, thus, the egg component or other vaccine additives (that may have been the cause of a previous reaction) may be in a higher quantity and cause a potentially severe reaction.
Patients that test positive to either egg protein or flu vaccine (whether seasonal or H1N1) and desire flu vaccination should only be given the vaccination by a board certified or board eligible allergist who after, careful evaluation, feels the potential benefit outweighs the risk.
Published On: October 26, 2009