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Vaccine Safety

Information and materials for health care providers to help address misconceptions and concerns about vaccine safety

Vaccines are among the most strictly regulated and effective tools of modern medicine. The Public Health Agency of Canada credits vaccines as saving more lives in the past 50 years than any other health intervention. However, vaccines have become a victim of their own success. There has been a shift from fear of disease to fear of the safety of vaccines. 

Vaccine safety is often a topic of media attention. Vaccine misconceptions can quickly gain momentum in the media despite the lack of scientific credibility. The resulting vaccine hesitancy can undermine the success of vaccine programs and can ultimately lead to lower coverage rates, which increase a population’s susceptibility to disease outbreaks.

Vaccine development

‎Vaccines are rigorously tested over the course of their development. Laboratory and animal testing are first conducted before vaccines are studied for use in humans. Testing in humans is done over three phases of clinical trials. These trials provide crucial information on vaccine safety as well as efficacy. Once vaccine manufacturers have successfully completed all three phases of the clinical trials, they must submit the data to Health Canada’s Biologic and Radiopharmaceutical Drugs Directorate (BRDD) for approval. 

Vaccine approval

The Biologic and Radiopharmaceutical Drugs Directorate (BRDD) is the Canadian regulatory authority responsible for approving biological drugs, including vaccines, for human use in Canada. The following are steps the BRDD has in place to ensure vaccine safety:

  • Before approval, the BRDD has regulatory processes to ensure that laboratory and clinical studies provide evidence of product safety and that products meet the highest standards of quality. 
  • Before and after approval, the BRDD has regulatory processes to ensure the highest quality of manufacturing is used to produce vaccines. 
  • Vaccine manufacturing facilities are inspected to ensure good manufacturing practices. 
  • Every new lot of vaccines produced must be authorized for release by BRDD to ensure that it is compliant with the parameters in the initially approved lots.

For more information, refer to The Regulation of Vaccines for Human Use in Canada (Health Canada). 

Vaccine recommendations

Once a vaccine has been approved for use in Canada by BRDD, recommendations about how to use these vaccines are then made by Canada’s National Advisory Committee on Immunization (NACI). This committee is made up of experts in the fields of pediatrics, infectious diseases, immunology, medical microbiology and public health. NACI makes recommendations for who should receive certain vaccines based on the burden of illness in Canada, as well as vaccine efficacy or effectiveness and safety.

In BC, recommendations to the Ministry of Health for public funding of vaccine in the province are made based on consideration of NACI recommendations, including those related to safety, but also of factors such as provincial epidemiology and health economics and of several implementation parameters. The Ministry makes a decision taking into consideration other health priorities.

Monitoring vaccine safety

Despite the crucial role that clinical trials play, these alone cannot detect the occurrence of rare adverse events. For this reason, post-marketing vaccine surveillance of safety on a population level is needed to help ensure vaccine safety.

In Canada, there are several systems in place that monitor vaccine safety. Through Canada’s active and passive surveillance systems, vaccine safety is closely monitored.‎

IMPACT (Immunization Monitoring Program ACTive), is a pediatric hospital-based national active surveillance network for adverse events in children following immunization, vaccine failures and selected infectious diseases that are, or will be, vaccine preventable. This network consists of 12 pediatric hospitals across Canada. A designated nurse at each of these hospitals uses several methods to identify children hospitalized with specific conditions and determines whether one or more vaccines were given prior to the hospitalization that could be related to the event. These events are reported to the local Medical Health Officer and to the Public Health Agency of Canada.


CAEFISS (Canadian Adverse Events Following Immunization Surveillance System) is the national population-based reporting system operated by the Public Health Agency of Canada. This system receives adverse events following immunization (AEFI) reports from all provinces and territories, as well as several federal departments. CAEFISS staff exchange information about potential safety signals with the Marketed Health Products Directorate and with the global vaccine safety office of the World Health Organization.

The infographic Vaccine Safety Matters: How Vaccines are Monitored illustrates the various levels involved in monitoring vaccine safety. Click for full-size image.

Health care providers play an important role in informing those receiving vaccines about common vaccine side effects and how to manage these at home. Vaccine recipients are also informed about potential serious adverse events following immunization (AEFI), which are uncommon. Prior to every immunization, the provider has a responsibility to conduct a health assessment and review whether the person has contraindications to vaccine receipt in order to avoid many serious adverse events, including anaphylaxis, a sudden and serious form of allergy. 

reporting aefi following immunization infographic


Counselling the public

Research has shown that concerns about vaccine safety can delay or prevent individuals from receiving recommended immunizations. Serious adverse events following immunization (AEFI) are very rare. However even expected and common reactions can be a cause for concern for some and may impede their confidence in receiving future immunizations.

Health care providers play a crucial role in communicating facts about vaccine safety to their clients. Like all other medical interventions, vaccines have risks. These risks must be carefully weighed against the risk of disease. The following resources can assist health care providers in addressing client’s concerns regarding vaccine safety.

SOURCE: Vaccine Safety ( )
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