Mr. Speaker, Health Canada has authorized several COVID-19 vaccines for use in Canada. Each of these underwent a careful scientific review and met our standards for safety, efficacy and quality. Information about all of the authorized vaccines including the regulatory decision summary can be found on the COVID-19 vaccines and treatments portal: https://bit.ly/3EH07IB. Users must click on the individual vaccine names and then the “all resources” tab.
For each of the vaccines that have been authorized, you can access detailed information such as the product monograph, which is the prescribing information for both consumers and healthcare professionals, or manufacturer insert; the summary basis of decision, which provides a detailed overview of the data considered by Health Canada; and the terms and conditions placed on the authorizations, which are the requirements for further data submission that manufacturers are required to meet
Note that information in the portal is being updated regularly. Users can also find all the clinical study reports related to the approval of Pfizer-BioNTech’s Comirnaty vaccine on Health Canada’s public release of clinical information website: https://bit.ly/3GFvDHE. Specific details related to various aspects of the review, including the summaries of the clinical efficacy and safety, can be found there.
As the federal regulator, Health Canada requires that clinical trial results be generated from properly designed protocols so that safety and efficacy of vaccines can be well demonstrated. Health Canada also requires manufacturing data demonstrating consistency and quality in the production of the vaccine. These requirements are informed by science and are aligned with international standards, including the World Health Organization, or WHO, guidelines.
With regard to Health Canada’s approval of the Pfizer COVID-19 vaccines and part (a) of the question, Health Canada followed the internationally accepted guidelines from the WHO for vaccine evaluation stating that the “Pharmacokinetic studies (e.g. determining serum or tissue concentrations of vaccine components) are normally not needed”.
Pfizer conducted non-clinical pharmacokinetic studies that evaluated the biodistribution as well as the metabolism and excretion of the BNT162b2 (V9) LNP formulation. Results of the biodistribution study in mice demonstrated positive biodistribution data. Metabolism studies demonstrated slow metabolism by hydrolysis and also showed formulations to be excreted.
With regard to part (b) of the question, clinical pharmacokinetic studies were not required for this vaccine evaluation. For vaccines, only dose-immunogenicity studies are performed. This is because vaccines are meant to directly induce immunogenicity by locally recruiting immunocytes that will carry on with the pursuing immunogenic processes. Thus, the clinical outcome from vaccines is determined mainly by an immunological response phase.
With regard to part (c), the product monograph notes that genotoxicity studies were not considered relevant to this type of vaccine. Genotoxicity studies are normally not required based on section 4.2.3 of the WHO guideline:
Part (d) of the question is not applicable.
With regard to part (e), the product monograph notes that carcinogenicity studies were not considered relevant to this type of vaccine. Carcinogenicity studies are normally not required based on section 4.2.3 of the WHO guideline.
Part (f) of the question is not applicable.
With regard to part (g), toxicology, developmental and reproductive studies were conducted on animals prior to the clinical studies. No safety concerns were identified from the non-clinical toxicology, developmental and reproductive studies. As per these findings, there were no recommendations for further toxicology, developmental or reproductive studies to be conducted on humans.
Furthermore, the vaccine safety component was further studied in human clinical trials. The human clinical trials indicated that the vaccine was well tolerated by participants and there were no findings of important safety concerns.
The product monograph indicates that non-clinical data revealed no special hazard for humans based on conventional studies of repeat dose toxicity.
With regard to part (h) of the question, the clinical trials for Pfizer vaccines were not designed to test transmission. The vaccine effectiveness for prevention of COVID -19 was tested and demonstrated in clinical studies. It is important to note that the clinical trials for the COVID-19 vaccines were designed to measure vaccine safety as well as efficacy against the prevention of severe illness, rather than transmission, which involves becoming infected and then passing the virus on to another person. Although not a part of the clinical trial process, evidence with respect to effectiveness against transmission was established by a number of peer-reviewed studies from domestic and international sources, such as the U.K. and Israel, along with other sources as noted. Further, the public health and published post-authorization real-world data have demonstrated the effectiveness of the COVID-19 vaccines in reducing the transmission of SARS-CoV-2. For example, Public Health Ontario published a literature review including both Canadian and worldwide data showing that COVID-19 vaccines can reduce transmission by 50% to 90% to other individuals, including transmission within households and long-term care homes.