Five Facts one must know about Allergy to Vaccines

Dr Derek Chu fellow in clinical immunology and allergy in the Department of Medicine and Zainab Abdurrahman an assistant clinical professor in the Department of Pediatrics at McMaster University have released 5 facts about allergies to vaccines that have appeared in Canadian Medical Association Journal (CMAJ).

Only one in 760,000 vaccinations will respond with anaphylaxis. For all other side effects, there are ways around any problem. Immediate allergic reactions or anaphylaxis to vaccines are rare. These reactions usually start within minutes following the vaccination and are characterized by the same symptoms as immediate reactions to other allergens; skin manifestations (urticaria, swelling, itching), respiratory manifestations (cough, difficulty breathing, wheezing) and a reduction in blood pressure (weakness, loss of consciousness). When symptoms might be due to an allergy (for example urticaria, redness, itching) but follow several hours or days after having received the vaccination, it is unlikely to be a true allergy to the vaccine.

Contraindications and precautions to vaccination are conditions under which vaccines should not be administered. Because the majority of contraindications and precautions are temporary, vaccinations often can be administered later when the condition leading to a contraindication or precaution no longer exists.

Five things to know about vaccine allergies are:

• 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 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.