In this letter to the Editor of the journal, the authors describe a retrospective review of patients who received influenza vaccination at a single allergy clinic in Philadelphia between 2007 and 2009. They reviewed each chart for any record of an anaphylactic reaction to egg. H1N1 vaccinations were excluded. Overall, 119 vaccinations were performed on 56 patients with egg-induced anaphylaxis and a vaccination reaction occurred in 3 doses (2 patients). Skin prick tests (SPTs) were carried out prior to vaccination to guide vaccine dosing. The authors present a summary of their findings and the main results found:
• Mean age at the time of vaccination was 4 years and 6 months (range, 7 months-13 years and 8 months).
• In all but 18 cases, the date of the most recent egg-induced anaphylactic episode was known.
• The most recent anaphylactic episode preceded the vaccination in 56 cases.
• Average time between egg anaphylaxis and vaccination was 26 months (range, 5 days-71 months).
• In 45 cases, although egg allergy was identified through SPT responses, history, or both before influenza vaccination, egg-induced anaphylaxis occurred after vaccine administration.
• In all, 113 vaccinations were preceded by influenza vaccine SPTs.
The authors write, “We report on the relative safety of influenza vaccination in subjects with a history of egg-induced anaphylaxis. Although practitioners should always be prepared to treat allergic reactions as they occur, here we demonstrate only mild reactions. In 119 vaccinations there were 3 cases of skin-limited reactions and no systemic reactions.” They add, “Influenza SPTs were not helpful in predicting who would or would not react. Of note, 7 patients who had positive influenza SPT responses tolerated single-dose vaccination, suggesting that vaccination dose division might not be necessary.” They note limiting factors to their study and conclude, “Nonetheless, our study adds to growing data that influenza SPTs and division of vaccination doses might be unneeded practices.”