Interpretation of Suspected Adverse Reaction Data

The following limitations should be taken into account when interpreting the suspected adverse reaction report data:

  1. The data has been collected primarily by a spontaneous surveillance system in which suspected adverse reactions to health products are reported to market authorization holders (manufacturers) and Health Canada on a voluntary basis.
  2. There is under reporting of adverse reactions with both voluntary and mandatory surveillance systems.
  3. Adverse reaction 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, and 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 and 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 adverse reactions associated with health products. Additional scientific investigations are required to validate signals from the Canada Vigilance Program and to establish a cause and effect relationship between a health product and adverse reaction. Assessment of causality must include other factors such as temporal associations, the possible contribution of concomitant medication or therapies, the underlying disease, and the previous medical history.
  5. This database contains only a small proportion of adverse reactions reported following receipt of vaccines, and is reflective of serious reactions reported to market authorization holders as required under the Food and Drugs Act. The majority of reports of these reactions 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 incidence 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 the data in these line-listings.
  8. Where a health product has multiple ingredients, it may not be possible to determine which, if any, of the substances in the combination product were responsible for a particular reaction.
  9. In order to be entered into the database, information from adverse reaction report is coded using key words (reaction terms) which represent the reaction(s) described in the case report. The coding of adverse reaction 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) and should not be used in isolation to make decisions regarding an individual's treatment regimen; other sources of information, including the prescribing information for the product, should be consulted.
  11. The assistance of a health care professional should be sought to aid in the interpretation of the information contained herein.
  12. The database is routinely checked for duplicate reports. Duplicate reports are reports related to the same patient and event received from more than one source (e.g., pharmacist and consumer). It is not always possible to detect duplicate reports, often because the documentation in the original report may be variable or incomplete. Each duplicate report received will appear separately on the summary and 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 from the Canada Vigilance Adverse Reaction Online Database is provided with the understanding that it will be appropriately referenced and used in conjunction with the Caveat.

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