Influenza Vaccines May Vary in Amount of Allergenic Components

People with egg or gelatin allergies shouldnt assume that just because theyve had a flu shot safely in the past they will be able to again, according to a new study, presented by Amber M. Patterson, MD, from Ohio State University and Nationwide Children's Hospital in Columbus, Ohio, at the American College of Allergy, Asthma and Immunology annual meeting in Phoenix Nov. 11-16, 2010.


Researchers found influenza vaccines (seasonal and H1N1) can contain different amounts of allergenic components, most commonly egg and/or gelatin. These varying amounts of egg and gelatin mean people who are allergic cant assume the flu shot they are getting wont cause a reaction, say researchers.


Allergists suggest that any egg- or gelatin-allergic patient, or anyone with history of severe reaction to any type of influenza vaccine, be tested to the specific vaccine lot number they will be given prior to immunization. It should never be assumed that tolerating one dose of influenza vaccine suggests future tolerance, say the authors.


Egg allergy is the second most common food allergy in children, affecting 1.5-3.2 percent of children. Sixty-eight percent of children outgrow egg allergy by age 16. An allergist can help identify egg allergies and discuss options for flu shots. Since about 70 percent of asthmatics also have allergies, people with asthma should discuss the importance of getting vaccinated with their allergist.