Influenza vaccination in individuals with egg allergy Authors John M Kelso, MD Julie Wang, MD Section Editor Scott H Sicherer, MD, FAAAAI Deputy Editor Elizabeth TePas, MD, MS Last literature review version 19.1: January 2011 | This topic last updated: February 9, 2011 (More) INTRODUCTION Both the intramuscular inactivated and intranasal live-attenuated influenza vaccines are cultured on fluid from chicken embryos As a result, there is a small amount of egg protein in these vaccines Thus, there is a potential risk of inducing an allergic reaction when administering the influenza vaccine to an individual with egg allergy INTRODUCTION However, many of these same patients are also at higher risk of an adverse outcome due to influenza infection (eg, age Thus, the presence of a positive skin test to influenza vaccine is not necessarily predictive of a subsequent reaction Irritant reactions False positive irritant skin test reactions are also possible, particularly with intradermal testing at concentrations of 1:10 or undiluted One study of 20 healthy adult volunteers without histories of vaccine reactions evaluated rates of false positive results in response to prick and intradermal skin testing with 10 common vaccines [28] False positives were not seen with prick testing, but false positive rates of 15, 55, and 65 percent were seen on intradermal testing with 1:100, 1:10, and undiluted concentrations of influenza vaccine, respectively Administration protocols The administration of influenza vaccine to an egg-allergic patient is a relatively common clinical dilemma The risk of a serious allergic reaction to the vaccine needs to be weighed against the risks of severe illness and death due to influenza infection and secondary complications Administration protocols The American Academy of Pediatrics (AAP), the United States Centers for Disease Control and Prevention, and the National Institute of Allergy and Infectious Diseases (NIAID) in the United States note the relative contraindication to administration of the influenza vaccine in patients with severe egg allergy or anaphylaxis, but acknowledge that vaccination may be indicated in certain individuals in whom the benefits outweigh the risks Two-step protocol The two-step protocol is considered a graded challenge This procedure should be administered only under close observation by personnel prepared to recognize and treat anaphylaxis Administer one-tenth of the inactivated vaccine dose intramuscularly followed by a 30 minute observation period If no reaction is noted, then administer the remaining nine-tenths dose intramuscularly followed by an observation period of at least 30 minutes SUMMARY AND RECOMMENDATIONS The large majority of patients with egg allergy are young children, although this allergy can persist into adulthood Many patients with egg allergy are at increased risk of influenza complications, including young children and those with a history of asthma or wheezing SUMMARY AND RECOMMENDATIONS Both the intramuscular inactivated and intranasal live-attenuated influenza vaccines contain a small amount of egg protein Safe administration of injectable influenza vaccine containing ≤1.2 mcg ovalbumin/mL to egg-allergic recipients has been reported SUMMARY AND RECOMMENDATIONS The risk of a serious allergic reaction to the vaccine needs to be weighed against the risks of severe illness and death due to influenza infection and secondary complications SUMMARY AND RECOMMENDATIONS For the patient who is six months of age or older and has known egg allergy of any severity, we suggest administration of an age-appropriate, approved vaccine that contains the lowest ovalbumin per dose without prior vaccine skin testing, followed by a 30 minute observation period in a facility prepared to recognize and treat anaphylaxis (Grade 2C) SUMMARY AND RECOMMENDATIONS Vaccine options are shown in the table (table 3) For most patients, we suggest administration of the vaccine as a single dose (Grade 2C) However, a two-step protocol is a reasonable alternative, especially for patients with a history of anaphylaxis to egg or when a low ovalbumin vaccine is not available Xin chân thành cảm ơn