Important potential food allergens in vaccines include egg and gelatin. Rare cases of reactions to yeast, lactose and casein have been reported.
It is strongly recommended that when vaccines are being administered resuscitation equipment must be available to manage potential
anaphylactic reactions, and that all patients receiving a vaccine are observed for a sufficient period.
Children who are allergic to egg may safely receive the measles-mumps-rubella (MMR) vaccine; it may also be given routinely in primary
healthcare settings. People with egg allergy may receive influenza vaccination routinely; however, some authorities still perform prior skinprick
testing and give two-stage dosing. The purified chick embryo cell culture rabies vaccine contains egg protein, and therefore the human
diploid cell and purified verocell rabies vaccines are preferred in cases of egg allergy.
Yellow fever vaccine has the greatest likelihood of containing amounts of egg protein sufficient to cause an allergic reaction in allergic
individuals. This vaccine should not be routinely administered in egg allergic patients and referral to an allergy specialist is recommended,
as vaccination might be possible after careful evaluation, skin-testing and graded challenge or desensitisation.