Millions of routine childhood vaccinations are given every year and allergic reactions from these vaccines are extremely rare. However, some people with certain food allergies may be at higher risk of allergic reactions as a result of vaccines containing certain food proteins.
Up to 8% of children suffer from food allergies, with egg being one of the most common foods to which children are allergic. Many routine childhood immunizations contain traces of egg protein and as a result, there is the possibility that a child with egg allergy will experience anaphylaxis (a severe allergic reaction) as a result of receiving a vaccination.
The following immunizations may contain egg or egg-related proteins:
influenza (flu). measles-mumps-rubella (MMR), yellow fever and typhoid vaccines.
Influenza vaccine and Egg Allergy
People with egg allergy have long been told to avoid the seasonal influenza vaccine because it contains small amounts of egg protein. This has led to withholding the vaccine from people with egg allergy, including those who may be at higher risk from complications from influenza infection, such as those with asthma. However a 2011 report from the American Academy of Allergy, Asthma and Immunology (AAAAI), has shown that the influenza vaccine is safe for most people with egg allergy. The report points to numerous studies that showed that even those with a history of anaphylaxis to egg generally tolerated the influenza vaccine. Even so, the AAAAI recommends caution when giving the influenza vaccine to egg-allergic people, and urges doctors to follow one of two protocols for vaccination.
First, physicians can give one-tenth of the vaccine dose, and monitor the person for 30 minutes. If no allergic reaction occurs, then the remainder of the vaccine is given and the person is monitored for another 30 to 60 minutes.
Second, the person can simply be given the entire vaccine at once, but should be closely monitored for at least 30 minutes by a physician in a setting where anaphylaxis can be treated.
The MMR vaccine and Egg Allergy
The MMR vaccine is produced in chick fibroblast cultures so the vaccine most likely does not contain egg proteins to which a person with egg allergy would react. Most people, even those with a severe egg allergy, do not have an allergic reaction to the MMR vaccine. The American Academy of Paediatrics recommends that children with egg allergy can be given the MMR vaccine without any special measures being taken. It would be reasonable, however, to monitor an egg-allergic child in the physician’s office for a period of time after giving the MMR vaccine.
Yellow fever vaccine and Egg Allergy
Yellow fever vaccine, a non-routine vaccine given to people travelling to Central/South America and sub-Saharan Africa, contains significant amounts of egg proteins and should not be given to people with egg allergy.
It contains the highest amount of egg protein of all the egg-based vaccines and has also been reported to cause allergic reactions in people with an allergy to chicken meat. As with the influenza vaccine, the yellow fever vaccine may be able to be given to egg-allergic people in small amounts over many hours, under close monitoring by a physician.