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Reported Side Effects - Disclaimers

Report a side effect

The Drug and Health Product Register's (DHPR) reported side effects section uses data collected through the Canada Vigilance Program. This page provides further detail on the source, nature and limitations of that content..


A caveat is a warning to the user and includes conditions and limitations.

This caveat relates to information taken from side effect reports that are submitted to Health Canada by health professionals and consumers. Submissions are either directly to Health Canada or via market authorization holders (manufacturers and distributors). Each report represents the suspicion, opinion, or observation of the individual making the report.

The Canada Vigilance Program is a spontaneous reporting system. It’s designed to detect signals of potential health product safety issues during the post-market period. A spontaneous reporting system is a passive surveillance system that encourages health professionals to report adverse reactions. Data is collected primarily by a this spontaneous surveillance system.

The side effects to health products are reported on a voluntary basis as they occur or are noticed. However, we are aware that side effects are often under-reported to both voluntary and mandatory spontaneous surveillance systems.

We’re unable to show the total number of reactions occurring or the number of patients exposed to the health product. Therefore, the number of adverse reports in the database should not be used:

  • for estimating the risk of a particular product
  • as a basis for determining the incidence of a reaction

Because of the multiple factors that influence reporting, quantitative comparisons of health product safety cannot be made from the data. Quantitative comparisons look at the total number of times an adverse reaction occurs. Some of these factors include the length of time a drug is marketed, the market share, size, and sophistication (experience) of the sales force, publicity about a side effect and regulatory actions. In some cases, the reported clinical data is incomplete and there is no certainty that the health products caused the reported reaction. A given reaction may be due to an underlying disease process or to another coincidental factor. This underlying disease process means a reaction is not caused just by the drug, but by the disease.

The information is provided with the understanding that the data will be appropriately referenced and used in conjunction with this caveat statement.

Interpretation of suspected side effect data

The following limitations should be taken into account when interpreting the suspected side effect report data.

  1. The data has been collected primarily by a spontaneous surveillance system. Suspected side effects to health products are reported to market authorization holders (manufacturers) and Health Canada on a voluntary basis.
  2. There is under-reporting of side effects with both voluntary and mandatory surveillance systems.
  3. Side effect reports are suspected associations which reflect the opinion or observation of the individual reporter. The data presented reflects, as much as possible, the reporter's observations and opinions. It does not reflect any Health Canada assessment of association between the health product and the reaction(s).
  4. Inclusion of a particular reaction does not necessarily mean that it was caused by the suspected health product(s). Certain reported reactions may occur spontaneously. They provide a background rate in the general population. They may have a temporal, but not necessarily a causal, relationship with the health product. The purpose of the Canada Vigilance Program is to detect possible signals of side effects associated with health products. Additional scientific investigations are required to validate signals from the Canada Vigilance Program. They are also needed to establish a cause and effect relationship between a health product and a side effect. Assessment of causality must include other factors such as:
    • temporal associations
    • the underlying disease
    • the previous medical history
    • the possible contribution of concomitant medication or therapies
      • concomitant medication is a drug taken by a subject during a clinical trial
  5. This database contains only a small proportion of side effects reported following receipt of vaccines. It’s reflective of serious reactions reported to market authorization holders as required under the Food and Drugs Act. The majority of reports for these side effects are submitted to the Canadian Adverse Events Following Immunization Surveillance System (CAEFISS)
  6. The number of reports received should not be used as a basis for determining the cause of a reaction, as neither the total number of reactions occurring, nor the number of patients exposed to the health product is known.
  7. Numerical comparisons should not be made between reactions associated with different health products on the basis of this data. Numerical comparisons are made when looking at the total number of reported adverse reactions for one drug to another.
  8. It may not be possible to determine the substance(s) in a combination product responsible for a particular reaction. A combination product has multiple ingredients. Multiple ingredients occur when a health product uses 2 or more drugs in combination.
  9. To be entered into the database, information from side effect reports must be coded using keywords (reaction terms). These represent the side effect(s) described in the report. The coding of side effect reports is subject to limitations of coding terminology dictionaries. Each report relates to a single patient, however, more than one reaction may have been described and therefore coded per case report.
  10. The data provided do not represent all known safety information concerning the suspected health product(s). It should not be used in isolation to make decisions regarding an your treatment regimen. Other sources of information, including the prescribing information for the product, should be consulted.
  11. You should get assistance of a health professional to aid in the interpretation of the information contained herein.
  12. The database is routinely checked for duplicate reports. Duplicate reports are those related to the same patient and event received from more than a single source. This could mean a report from both a pharmacist and consumer. It’s not always possible to detect duplicate reports. This is because documentation in the original report may be incomplete or described differently. Each duplicate report received will appear separately on the summary. They will be identified as duplicate in the “Link/Duplicate Report Information” field.
  13. When follow-up reports of a single case or event are received, only the latest version of the report is included in the output.

Information on this system is provided with the understanding that it will be appropriately referenced and used in conjunction with the listed caveat.

Privacy Statement

The side effect reporting program is called the Canada Vigilance Program. This program collects personal information as per Section 4 of the Department of Health Act. Its purpose is to:

  • manage risk
  • monitor licensed products
  • detect potential safety issues and trends
  • improve the safe use and efficacy of the health products

Information related to the identity of the patient and/or reporter will be protected as personal information under the Privacy Act, and in the case of an access to information request, under the Access to Information Act.

Suspected health product side effect-related information that’s voluntarily submitted to Health Canada is maintained in a secure computerized database. The program endeavours to use and disclose only de-identified (anonymous) information. However, we may use and disclose personal information that’s not de-identified as permitted under the Privacy Act. This can legally occur when an incident is life-threatening to the general population.

Further details regarding the personal information collected under this program are available. Visit the Personal Information Bank, Health Canada, Health Products and Food Branch, Branch Incident Reporting System, PIB#PPU 088.

You have the right to access your personal information and you are entitled to request correction to ensure accuracy of your information.

If you wish to exercise this right, contact the Treasury Board of Canada Secretariat.

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