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Frequently Asked Questions

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Are vaccines safe?

Vaccines are safe, with huge benefits to children's health - all through their lives. Most vaccine side effects are minor and self-limited, lasting only a few days and not disrupting daily activities. Serious allergic reactions from vaccines are extremely rare and are reported immediately to the Public Health Agency of Canada so that any problems can be dealt with quickly.

Safer than diseases they prevent

Vaccines in Canada are effective and safe--much safer than the 13 diseases they prevent. These diseases can lead to pneumonia, deafness, brain damage, heart problems, blindness, paralysis and carry a risk of life-long disability or death.

Rigorous research is ongoing

Vaccines are continuously monitored and tested around the world and in Canada before they are approved for use. Canada has several systems in place to keep a watchful eye on any reports of unusual, adverse side effects following immunizations.

False fears about harmful effects

All parents have questions about the risks associated with immunization. Some people worry that vaccines can cause health problems, such as autism or sudden infant death syndrome (SIDS). Expert research committees in Canada and around the world have investigated reports of serious effects over many years. They have found no evidence of a link between vaccines and autism or any other illnesses.

Should you experience an adverse event following immunization, please ask your doctor, nurse, or pharmacist to complete the Adverse Events following Immunization (AEFI) form.

For more information, please consult:

The relevant product monograph has information as well (especially section 3 for the public). Also, make sure you question the health professionals (physicians and/or nurses for any vaccine-related health information you need.

What is in place to make sure vaccines are safe as possible?

The Biologics and Genetic Therapies Directorate (BGTD) of Health Canada works to ensure the safety and effectiveness of vaccines.

Steps that are in place to ensure vaccine safety:

  1. Vaccines are only approved if there is sufficient evidence that they are both effective and safe with a high margin of safety.
  2. Before licensure, regulatory processes called 'Good laboratory', and 'Good clinical practices' ensure that lab and clinical studies done to provide evidence of product safety meet the highest standards of quality.
  3. Before and after licensure, regulatory processes called 'good manufacturing processes' are in place to ensure the highest quality of manufacturing is used to produce vaccines.
  4. Vaccine manufacturing facilities are inspected and given a license by regulators.
  5. Every new lot of vaccines produced has to be cleared by regulators before approval to sell in Canada. The 'lot release' program is meant to ensure, to the extent possible, that each new lot of vaccine matches the lots used to establish safety and effectiveness that were the basis for licensure.
  6. Regulators and Public health authorities continuously monitor vaccines after they have been approved to detect any previously unrecognized safety concerns – for the product as a whole, for a new lot or for population subgroups that may have a higher risk of selected adverse reactions.
  7. Vaccine safety is an international concern. Information on possible safety concerns is communicated very rapidly among different countries. This careful monitoring ensures that public health authorities can act quickly to address concerns. In addition, research continues to improve vaccines.

Surveillance of Vaccine Safety

In Canada, we have two systems that support the continued surveillance of approved vaccines:

What are the risks and benefits of vaccines?

Even with some proven side effects, vaccines are very safe since they are usually given to healthy individuals. And the risks from the disease being prevented are always much higher than any vaccine-associated risk.

In considering the safety of vaccines, you should look at the risks and benefits. If there were no benefit from a vaccine, even one serious side effect in a million doses could not be justified. If there were no vaccines, however, there would be many more cases of diseases, more serious side effects from disease, and more deaths.
For information on the difference vaccines make in terms of benefits please see Table 2. Incidence of Select Vaccine-Preventable Diseases in Canada - Pre-vaccine Era Compared with Five Most Recent Years.

The dangers of vaccine-preventable diseases are many times greater than the risks of a serious adverse reaction to the vaccine. Just compare with countries that have stopped or decreased their immunization programs. They pay a heavy price as the diseases return stronger and more powerful than ever. Vaccine-preventable diseases can lead to pneumonia, deafness, brain damage, heart problems, blindness and paralysis in children who are not protected.

We are fortunate in Canada to have vaccines for diseases that still kill and disable children throughout the world every day. For information on who should not receive specific vaccines, please see the Contraindications and Precautions section of each vaccine chapter in the Canadian Immunization Guide, 7th Edition 2006.

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