Various routine childhood vaccinations are given every year and allergic reactions from these vaccines are considered extremely rare. Nevertheless, some individuals with certain food allergies might be at higher risk for allergic reactions since some vaccines might contain certain food proteins.
Children usually suffer from food allergies, particularly egg as the top allergen. Several routine childhood immunizations contain minimal traces of egg protein or other food components. As a consequence, there is the possibility that a child with food allergies will end up with anaphylaxis after receiving a particular vaccination. Certain foods are present in small amounts in routine childhood vaccinations as well as non-routine vaccines.
Egg
Children with egg allergy have been a big concern when receiving childhood vaccines. The routine childhood immunizations that may contain egg or egg-related proteins include measles-mumps-rubella (MMR) and influenza (flu) vaccines. In addition, non-routine vaccines such as typhoid and yellow fever vaccines contain egg protein.
The influenza (flu) vaccine contains limited amounts of egg protein and this amount varies every year and by batch. Generally, the vaccine should not be given to those with a true egg allergy. Nevertheless, in certain circumstances, the benefit of receiving this vaccine outweighs the risks. The allergist might be able to administer the vaccine in small amounts over a number of hours while closely monitoring the individual for an allergic reaction.
As for the MMR vaccine, it is produced in chick fibroblast cell cultures. Remember that the vaccine does not contain egg proteins that an individual with egg allergy would react to. In most individuals, even those with severe egg allergy will not have an allergic reaction to the vaccine. A child with egg allergy can be given the MMR vaccine but must be monitored in the clinic after receiving the vaccine.
Gelatin
Gelatin is usually added to various vaccines as a heat stabilizer. The routine childhood vaccinations that contain gelatin include varicella (chickenpox), MMR, DTap (diphtheria, tetanus and pertussis) and influenza (flu).
The non-routine vaccines include rabies, yellow fever and Japanese encephalitis. Take note that allergic reactions to the MMR vaccine are more likely due to the gelatin rather than the residual egg proteins in the vaccine.
Baker’s yeast
There are certain vaccines synthesized by Saccharomyces cerevisiae which is the common baker’s yeast utilized in creating bread. The routing childhood vaccines that contain baker’s yeast include hepatitis B and any combination vaccine that contains hepatitis B.
An individual who experienced an allergic reaction after eating products that contain baker’s yeast must not be given the hepatitis B vaccine. Nevertheless, just like in cases with vaccinations that contain egg among individuals with egg allergy, the vaccines that contain yeast might be given to those who are yeast-allergic under the supervision and close monitoring of a doctor.