Most influenza vaccine package inserts with the exception of Flucelvax, using Madin Darby canine kidney cells for production, and Flublok, using armyworm cells for production, list an allergy to egg and egg protein as a contraindication to vaccination because most influenza vaccines are made using chicken eggs. Flublok, however, is the only flu vaccine considered completely egg-free.
In 2016, the CDC’s Advisory Committee on Immunization Practices (ACIP) revised flu shot recommendations for people with egg allergies and stated that individuals with an allergy to egg can receive any type of flu vaccine, whether manufacturers use chicken eggs for production or not. In 2022, CDC officials advised that individuals who develop hives from egg products may be vaccinated without any special precautions, while those who have experienced a severe anaphylactic reaction (one involving respiratory distress, angioedema or use of epinephrine) should be monitored in a setting where there is a health care professional trained to recognize and quickly treat an anaphylactic reaction. While CDC officials stated that allergic reactions could occur in individuals who are allergic to eggs, they considered the reactions to be rare and not serious enough to warrant a contraindication.
In 2023, the CDC dropped all warnings related to egg allergies and declared that no special precautions were necessary to ensure the safe administration of flu shots in egg allergic individuals. According to the CDC, individuals with egg allergies can receive any influenza vaccine indicated for their age and risk category without any added safety measures than those implemented for the administration of other vaccines.
Currently a severe allergy to a vaccine component or a history of a life-threatening allergic reaction to a previous flu shot are the only CDC approved official contraindications (medical reasons for not getting vaccinated) to receiving influenza vaccine. A history of GBS within six weeks of a previous flu vaccine, a severe egg allergy (i.e. respiratory distress, recurrent vomiting, angioedema, lightheadedness, treatment with epinephrine) or “moderate or severe acute illness with or without a fever,” are now only considered precautions to vaccination. According to the CDC, vaccination should be deferred in the presence of a precaution, but persons may receive the vaccine if the benefit of vaccination is believed to outweigh the risk.
