You’re probably not allergic to vaccines

Derek Chu (left) is a fellow in clinical immunology and allergy in the Department of Medicine and Zainab Abdurrahman is an assistant clinical professor in the Department of Pediatrics.


There is little chance you are actually allergic to vaccines and, if you are, your allergist can vaccinate you.

Only one in 760,000 vaccinations will respond with anaphylaxis. For all other side effects, there are ways to address any problems that arise.

Five facts about allergies to vaccines, pulled together by two McMaster University physicians, were published today in the Canadian Medical Association Journal. Derek Chu is a fellow in clinical immunology and allergy in the Department of Medicine and Zainab Abdurrahman is an assistant clinical professor in the Department of Pediatrics. The pair were also interviewed as part of a CMAJ podcast.

Five things to know about vaccine allergies

  • Immunoglobulin E (IgE)-mediated allergies to vaccines are extremely uncommon.

Responding to a vaccine with hives, swelling, wheezing or anaphylaxis happens in about one of 760,000 vaccinations. It will start within minutes of the vaccination, is unlikely to begin after 60 minutes and highly unlikely to occur after four hours.

  • Signs like fever, local pain or local swelling are not signs of allergy.

These responses to a vaccine may happen as much as seven to 21 days after a vaccination, but they are not an allergic reaction.

  • With the exception of the yellow fever vaccine, an egg allergy is no reason to avoid vaccinations.

No special precaution is needed when people who have an egg allergy have an influenza, MMR (mumps, measles and rubella vaccines given together), or rabies vaccination because the amount of egg protein it may contain is too minuscule, says the Public Health Agency of Canada and the Canadian Pediatric Society.

  • It may be a reaction to the rubber stopper.

If you have a latex allergy, it will be the rubber stopper or preloaded syringe, not the vaccine that causes a problem.

  • Your allergist can safely vaccinate you.

If you really do have a vaccine allergy, allergists can help immunize you through techniques such as graded administration, or giving the vaccine a little at a time.

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