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Frequently Asked Questions About Immunization

Do you have questions about immunization in Halton Region? Learn about immunization, specific vaccines, how they involve infants and school attendance.

General information

Canada has very strict guidelines for making vaccines, which include many safety tests carried out by Health Canada.

Certain materials - such as formaldehyde and aluminum - are used to kill bacteria and make vaccines as effective and safe as possible. The levels used in vaccines are lower than what a child would be exposed to on a day-to-day basis.

No, because children who are not immunized are at risk of becoming infected with diseases before their body is able to fight them.

Immunization (which is made up of parts of weak or dead viruses or bacteria) works by triggering the body’s immune system to make the proper immunity (memory) cells. Therefore, when germs enter the body at a later time, the memory cells kill the germs before they can infect the body. Vaccines are far safer than getting the disease.

These diseases no longer exist in Canada because our immunization programs have protected many Canadians from certain diseases, making it very hard for them to spread. This builds a circle of protection around a whole community, and protects those who cannot be immunized (e.g., for medical reasons).

Specific vaccines

There is no difference in the rate of autism between immunized and unimmunized children. Evidence-based reviews and research studies involving millions of children have found no connection between immunization and autism.


No, multiple immunizations protect your baby against multiple diseases as early as possible. We all come into contact with millions of germs a day, so the immune system will easily handle exposure to antigens (made up of parts of weak or dead viruses or bacteria) in multiple immunizations.

Breastfeeding gives babies a great start, but it will not protect them against all the specific diseases that immunization prevents.

Yes, your child’s immune system works so well that they can get all their shots, even if they are teething, have a fever, diarrhea or ear infection, or are taking antibiotics.

School attendance

Halton Region Public Health is continuing to work with the Ministry of Health on the enforcement of mandatory vaccines under the Immunization of School Pupil’s Act (ISPA) (external link).

All immunizations listed in the Publicly Funded Immunization Schedule are recommended.

However, specific immunizations are legally required for students attending school in Halton Region as per the ISPA.

Parents must provide proof that their children have the following immunizations to public health, in order for them to attend school:

  • Diphtheria
  • Rubella
  • Pertussis (whooping cough)
  • Tetanus
  • Varicella (chicken pox) – for those born in 2010 or later
  • Measles
  • Mumps
  • Polio
  • Meningococcal disease - (Men C-C) for ages 1-11 AND (Men C-ACYW) for ages 12 and older

For more information, download this Parent Handout developed by the Province of Ontario (external PDF), or contact Halton Region Public Health by emailing, or by calling 311.

A parent/guardian can temporarily or permanently exempt a child from receiving immunizations based on either of the following:

  • Medical reasons
  • Non-medical reasons (conscience or religious belief)

An exemption allows an unimmunized or under-immunized child to attend school. However, in the event of an infectious disease outbreak, the Medical Officer of Health has a responsibility to ensure that the child does not attend school until the outbreak is over.

Please visit the vaccine exemption web page for more information on this process.

The school collects and forwards immunization records to Halton Public Health only at the time of initial registration. After registration, parents are responsible for updating their child’s immunization records with the Health Department every time the child is vaccinated.

As your child gets older, there are additional immunizations and doses of vaccine required for them to be completely immunized for their age.

Check with your healthcare provider to make sure that your child has had all the vaccines needed to attend school. Don’t forget to report all immunizations to the Health Department. Your doctor’s office does not do this for you.