Influenza vaccines
Influenza vaccines include trivalent and quadrivalent inactivated vaccines (IIV), recombinant subunit vaccine (RIV) and live attenuated vaccine (LAIV) and mostly are grown in embryonated chicken eggs and, consequently, might contain small amounts of egg proteins, most notably ovalbumin, the amounts of which vary by vaccine manufacturer and lot. In the past, egg allergy was considered a contraindication to the administration of Influenza vaccines while, nowaday, it no longer contraindicates it and these patients can safely be vaccinated.
In fact, there is strong evidence that children with egg allergy, including those reporting anaphylaxis, could be safely immunized with IIVs containing less than 1.2 μg/ml of egg protein, either in two graded doses or in one single dose31, while a concentration of ovalbumin < 0.24 μg/dose in LAIVs was assessed as safe for children with egg allergy including anaphylaxis32,33.
In the absence of a prior history of anaphylaxis after egg consumption influenza vaccines can be administered without precautions while, when history of anaphylaxis is reported, in some guidelines it is recommended administering the vaccine without specific precautions34 while others recommend a prolonged observation period to 60 minutes and the presence of an equipped setting32,33.
A vaccine obtained from human diploid cells is also available as a safe alternative for egg allergic individuals26.