by Heidi Green
June 09, 2010

If you’ve ever had a flu shot, you’ve almost certainly been asked, “Are you allergic to eggs?” I’ve always wondered what the options are for those who answer, “Yes.” Are they denied the vaccine? Are they left unprotected from the flu?

The answer is no. No, egg-allergic patients without anaphylaxis do not need to be denied the vaccine. No, they won’t be left unprotected from the flu. Children without anaphylactic reactions to egg may safely receive the flu vaccine, in a controlled fashion.

Research
In a study recently published in the journal Pediatrics, researchers from Children’s Hospital Boston analyzed data from the medical records of egg-allergic patients between the ages of 6 months and 18 years who were vaccinated during the 2002–2003 or 2008–2009 flu seasons. In 2002–2003, an egg-allergic patient who had recently experienced egg-induced anaphylaxis would not have been immunized. A patient classified as egg-allergic but who consumed egg-containing foods regularly would have received a full-strength dose. All other egg-allergic patients were subjected to skin-prick testing. If the test result was negative, the vaccine would be administered as two doses: the first dose would be one-tenth of the recommended dose; the second would be the remaining nine-tenths.

By 2008–2009, Children’s Hospital Boston no longer used skin-prick testing in this process. Rather, egg-allergic patients without anaphylaxis or egg consumption were automatically allowed the two-dose vaccine.

In all cases, patients were monitored for approximately 30 minutes after vaccination, and adverse reactions were treated and recorded in their medical records.

As Dr. Erica Chung explains, skin testing is “time consuming and possibly unreliable in identifying children who will tolerate the vaccine.” Therefore, in this study, she and her colleagues “examined the rate of vaccine adverse reaction during the periods both with and without a vaccine skin test” to determine if it were beneficial to patients.

Results
The researchers found near identical results for the group of patients who underwent skin testing prior to vaccination and the group of patients who did not. Of the 56 children who underwent skin testing, 95 percent tolerated the vaccine without serious adverse events. In the group of 115 children who did not undergo skin testing, 97 percent tolerated it. In other words, eliminating the skin testing did not affect the rate of adverse reactions, and egg-allergic children were just as likely to tolerate the influenza vaccine with the skin test as without it.

The majority of adverse reactions identified were redness and swelling at the site of the injection. Far fewer patients experienced systemic reactions, such as wheezing and rash. No patients in this study experienced anaphylactic reactions.

Recommendations
The Centers for Disease Control and Prevention (CDC) recommends flu vaccination for all children between the ages of 6 months and 19 years, but recommendations for egg-allergic patients have varied. Vaccine manufacturers themselves list egg allergy as a contraindication for immunization.

As with so many decisions we make as parents, you’ll ultimately need to rely on your own judgment. But parents who wish to have their egg-allergic children receive the flu vaccine should:

• Discuss vaccination—especially the two-dose protocol recommended by Dr. Chung and colleagues—with their child’s health care provider. Find out if your health care provider’s standard is to administer the vaccine with or without skin-prick testing, and voice your preference.

• Make sure that the health care provider is equipped to deal with any adverse reactions which may occur. Dr. Chung and her colleagues note that vaccines in their study were administered by experienced staff equipped to manage possible serious adverse reactions.