Immunizations: Questions Parents Ask

Search Knowledgebase

Topic Contents

Immunizations: Questions Parents Ask

Common Questions

Immunizations help protect you or your child from disease. Most are given as shots. They are sometimes called vaccines, or vaccinations. Here are some common questions that parents ask about these shots:

Why should my child get immunized?


  • Protect your child from dangerous diseases and help to keep disease from spreading.
  • Cost less than getting treated for the diseases.
  • Have very few serious side effects.
  • Often are needed before a child can attend school or daycare.

When should my child be immunized?

Childhood immunization schedules may vary in each province and territory. Ask your doctor what shots your child should get.

Are immunizations really needed? Haven't we gotten rid of most diseases?

Only immunizations prepare your child's body to fight disease. Widespread immunizations in Canada have led to a sharp drop in diseases. Better living conditions have also helped, but they aren't enough to protect you from disease.

Dangerous diseases, such as polio, still exist in other countries. Travellers can bring them into Canada. So it's still very important to have your child immunized.

Do vaccines cause autism?

No link has been found between vaccines and autism.

Some parents worry that certain vaccines can lead to autism. Some stopped vaccinating their children altogether because of this concern.

It is much more dangerous to risk getting the diseases than to risk having a rare serious reaction to the vaccines.1, 2

What are the side effects of vaccines?

Most side effects from vaccines are minor, if they occur at all.

The area where the shot was given may be sore. And some children may be fussy or get a slight fever. Your doctor or pharmacist can explain the reactions that could occur.

People who are allergic to eggs may have a reaction to flu shots, which contain egg protein. If your child has an egg allergy, don't take him or her for a flu shot without talking to a doctor first.

Serious side effects are very rare. Again, it's much more dangerous to risk getting the diseases than to risk having a serious reaction to the vaccines.

Isn't it dangerous to get more than one vaccine at a time?

No. Combined vaccines have no greater risk for side effects than a single vaccine does.3

Some parents worry about their children getting several vaccines at the same time. They worry that a child's immune system can't handle all those vaccine organisms at the same time.

Getting more than one shot may seem like a lot for a child's body to handle. But babies have billions of immune system cells that are hard at work all the time, fighting the many thousands of germs they're exposed to every day.

More and more vaccines are being combined into a single shot, such as the measles-mumps-rubella shot. This means fewer shots need to be given. Even though the vaccines are combined, each gives the same protection as it would if it were given alone.

Is it okay to skip a shot when my child is sick?

On very rare occasions, your doctor may suggest waiting to have your child immunized. For example, you may need to wait when your child has:

  • A history of serious allergic reaction to a vaccine.
  • Severe vomiting or diarrhea, when dehydration is a concern.
  • A serious illness, such as pneumonia, bronchiolitis, or a severe asthma attack.

But children usually can still get a shot even when they have a minor illness. This includes a cold, an ear infection, vomiting, or diarrhea. And children usually can still get a shot when they are taking antibiotics.

Talk to your doctor if you have any concerns about having your child immunized.



  1. Centers for Disease Control and Prevention (2009). Vaccine safety: Mercury and thimerosal. Available online:
  2. Schechter R, et al. (2008). Continuing increases in autism reported to California's developmental services system. Archives of General Psychiatry, 65(1): 19–24.
  3. Atkinson W, et al., eds. (2007). Epidemiology and Prevention of Vaccine-Preventable Diseases, 10th ed. (The Pink Book). Washington, DC: Public Health Foundation. Also available online: [Errata and updates available online:]


By Healthwise Staff
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer John Pope, MD - Pediatrics
Last Revised August 5, 2010

Last Revised: April 5, 2012

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information.