Egg Allergy Not a Reason to Avoid Flu Vaccine After All

Having an egg allergy is not a reason to avoid getting the 2010-2011 flu vaccination. According to new recommendations from the American Academy of Allergy, Asthma & Immunology, anyone with a history of suspected egg allergy should first be evaluated by an allergist or immunologist for appropriate testing and diagnosis but can probably receive the vaccination.

Matthew J. Greenhawt, MD, MBA, clinical lecturer at the University of Michigan Health System and James T. Li, MD, PhD, chair of the Division of Allergic Diseases in the Department of Internal Medicine at Mayo Clinic, co-authored the guidelines based on recent studies one conducted at the University of Michigan -- that show that most egg-allergic individuals can receive the flu vaccine safely under the care of their allergist/immunologist.

In the past, people with egg allergy were told not to get the influenza vaccine because the vaccine contained egg protein and could trigger an allergic reaction. Research in the past year shows that influenza vaccines contain only tiny amounts of egg protein. Clinical studies have shown that the vast majority of persons with egg allergies did not experience a reaction when immunized with the influenza vaccine.

The safety of administering egg-containing immunizations to egg-allergic children and adults received new interest during the recent global pandemic of the H1N1 Influenza A virus in 2009-2010.

The H1N1 Influenza A vaccine (H1N1), like the seasonal Trivalent Influenza Vaccine (TIV) is grown on embryonated chicken eggs, which led to concerns that residual contamination of ovalbumin could provoke allergic reactivity in people with egg allergies. The 2010 influenza vaccine has incorporated the H1N1 strains. A single TIV is being offered this season.

Historically, though caution has been recommended in administering influenza vaccine to egg-allergic individuals, previous experience suggests that many people with diagnosed or suspected egg allergy can receive influenza vaccination successfully, if precautions are followed.

Examples of precautions that have been used include vaccine skin testing, a 2-step graded dose (10%, followed by 90% of the age appropriate dose after a brief observation period), or stepwise desensitization.

Given the urgency to protect children last year from the global influenza pandemic, investigative groups have re-examined the issue of the safety of this vaccine in egg-allergic people, and the field has advanced significantly since the last influenza season.

According to the new recommendations, the authors no longer recommend the practice of skin testing to the seasonal Trivalent Influenza Vaccine (TIV), although it may be useful as an extra level of caution in cases where the patient has a documented history of a past allergic reaction to the vaccine.

Anyone with a history of suspected egg allergy should first be evaluated by an allergist or immunologist for appropriate testing and diagnosis. Patients with a confirmed egg allergy can then receive the vaccine safely using one of two protocols: a two-step graded challenge or a single, age-appropriate dose.

"It is not necessary to withhold influenza vaccination from egg-allergic patients, says Greenhawt. "Our recommendations provide two flexible approaches to vaccination. Each approach is backed with recent evidence that it is safe. Most allergists should be able to identify with one of our recommended approaches, and as such, be able to vaccinate their egg-allergic patients with confidence."

Greenhawt notes that the safety of these vaccines in individuals with severe egg allergy needs to be studied further.

A few concepts bear further study, such as the safety of these vaccines in individuals with severe allergy to egg, but it appears that most egg-allergic patients can safely receive influenza vaccination if desired, Greenhawt says. Greenhawt is the lead investigator on a follow-up study that looks at the vaccines safety in severely egg-allergic patients.

Providers should no longer withhold the vaccine on account of a patients egg allergy, and should feel comfortable selecting the precautionary strategies for administering the influenza vaccine, he adds.

Reference: American Academy of Allergy, Asthma and Immunology, Oct. 2010