Finally, a multicenter study conducted by our group over 5 influenza vaccine seasons permitted a better estimate of the risk of allergic reaction. Four hundred and fifty-seven doses of trivalent inactivated influenza vaccine were administered to 367 patients of which 132 (153 doses) reported a severe allergic reaction to eggs[4]. Four patient reported possible mild reactions secondary to previous influenza vaccines (1 urticaria, 2 vomiting and 1 eczema), but no severe allergic reactions were observed during the study. Thirteen patients developed mild allergic appearing symptoms in the 24 hours following vaccine administration but none of the 367 patients developed an anaphylactic reaction. Using a 95% confidence interval (Clopper-Pearson exact CI), the obtained results of this study allowed us to estimate a risk of anaphylaxis between 0 and 0.08% (0 to 1 on 1250 doses) for global population of egg-allergic patients and between 0 to 0.62% (0 to 1 on 161 doses) for patients with history of severe allergic reaction to eggs.