Mr. Speaker, before a vaccine is approved in Canada, the department conducts a rigorous scientific review of its safety, efficacy and quality. Submissions typically contain extensive data regarding the vaccine's safety, efficacy and quality, including results of pre-clinical and clinical studies, details on manufacturing processes, and information on adverse events following immunization. An authorization is only issued when the benefits of the vaccine outweigh the risks of its use. After authorization, Canada has a robust and well-established vaccine safety surveillance system involving Health Canada, Public Health Agency of Canada or PHAC, provinces and territories, and vaccine manufacturers.
In response to (a), Health Canada received and reviewed the outcomes from clinical studies of COVID 19 vaccines, including the assessment for the theoretical risk of vaccine-associated enhanced disease, VAED.
VAED, antibody-dependent enhancement or ADE, and severe COVID-19 cases were considered adverse events of special interest that were followed by the independent safety data monitoring boards as part of COVID 19 clinical trials. VAED/ADE is considered an acute phenomenon resulting from exposure to the virus shortly following vaccination when the immune system may have a disproportional response to the virus. In the protocols for these trials, there were prespecified stopping rules that included monitoring for the onset of severe COVID 19 cases as part of the safety surveillance for the potential of VAED/ADE events during the conduct of the clinical trials.
The available data from the clinical trials suggested no evidence for VAED associated with COVID-19 vaccines. Research using suitable animal models for testing vaccine immunogenicity and enhanced disease did not demonstrate evidence of enhanced disease following vaccination. This has been tested with several different vaccine platforms, including mRNA vaccines.
In response to (b), see response to (a) and (e). While the outcomes of clinical trials did not demonstrate evidence of VAED associated with the use of COVID-19 vaccines, VAED was considered an important potential risk in all risk management plans of these products and has been monitored closely for authorized vaccines. This process allows Health Canada to assess information submitted by the manufacturer as it became available during the product life cycle and regularly assess whether there is any new safety information that may affect the benefit-risk profile of the product.
As with all health products, Health Canada continues to monitor the safety of COVID 19 vaccines. Should new safety issues be identified, Health Canada takes action, which could include communicating new risks to Canadians and health care professionals, requesting safety information from the manufacturers, or changing the recommended use of the product.
Further details about all authorized COVID-19 vaccines, including information on clinical trials conducted, can be found on the Government of Canada’s website “COVID vaccines and treatments portal”, at https://covid-vaccine.canada.ca/. Specifically, information about Comirnaty, by Pfizer-BioNTech, can be found at https://covid-vaccine.canada.ca/info/SBD00510-comirnaty-en.html; information about Spikevax, by Moderna, can be found at https://covid-vaccine.canada.ca/info/SBD00511-spikevax-en.html; information about Nuvaxovid, by Novavax Inc., can be found at https://covid-vaccine.canada.ca/info/SBD00581-nuvaxovid-en.html; information about Vaxzevria, by AstraZeneca, can be found at https://covid-vaccine.canada.ca/info/SBD00519-vaxzevria-en.html; information about Jcovden, by Janssen Inc., can be found at https://covid-vaccine.canada.ca/info/SBD00522-jcovden-en.html; information about Covifenz, by Medicago Inc., can be found at https://covid-vaccine.canada.ca/info/SBD00582-covifenz-en.html.
In response to (c), see response to (a) and (b).
In response to (d), following authorization, Canada has a robust and well-established vaccine safety surveillance system involving Health Canada, Public Health Agency of Canada or PHAC, provinces and territories, and vaccine manufacturers. Health Canada continues to monitor the safety profile of health products once they are on the Canadian market, to help ensure that the benefits of the product continue to outweigh the risks. The safety profile of these products is monitored by reviewing information from manufacturers and international regulators. When new safety issues are identified, Health Canada takes action, which could include communicating new risks to Canadians and health care professionals or changing the recommended use of the product. In addition, Health Canada and the PHAC have been actively monitoring and reviewing reports of adverse events following immunization, AEFI, including VAED, reported to the Canada vigilance program of Health Canada and the Canadian adverse events following immunization surveillance system of the PHAC. This information is published on the Government of Canada’s website. It is important to note that these reports do not necessarily imply that a relationship between the adverse event and the vaccine has been established. However, they are an important information source supporting ongoing safety monitoring.
In response to (e), as part of the ongoing pharmacovigilance monitoring for COVID-19 vaccines, no new safety signal has been identified for VAED to date. Furthermore, the information available at this time demonstrates that the benefits of COVID-19 vaccines continue to outweigh potential risks. Health Canada continues to monitor these vaccines as long as they are authorized and marketed in Canada.
In response to (f), see response to (d).
In response to (g), as described in (b) and (d), Health Canada and the PHAC have been actively monitoring and reviewing reports of adverse events following immunization, AEFI, reported to the Canada vigilance program of Health Canada and the Canadian adverse events following immunization surveillance system of the PHAC. This information is published on the Government of Canada’s website.
In addition, the National Advisory Committee on Immunization, NACI, primarily evaluates clinical and post-market observational data to support the development of recommendations on the use of vaccines in Canada.