Mr. Speaker, in response to part (a) of the question, the omicron variant of the SARS-CoV-2 virus was first reported in southern Africa in November 2021 and officially designated by the World Health Organization as a variant of concern with the Greek letter omicron on November 26, 2021. Within days of its appearance, preliminary analysis suggested that the variant may have a transmission advantage as compared to the delta variant of concern, though it would be some weeks later that vaccine effectiveness in terms of preventing transmission of omicron could be confirmed. By mid-December 2021, the Public Health Agency of Canada had sufficient evidence, including from international sources, that vaccine effectiveness against omicron infection and symptomatic disease after an mRNA primary series was lower than that for the delta variant.
As regards parts (b)(i), (b)(ii), (b)(iii) and (c) of the question, COVID-19 vaccines are defined by the manufacturer, and their intended use described in the product monograph, or label, as part of the information required when seeking regulatory authorization for these products in Canada. Health Canada, as a regulatory body, determines the terms and conditions under which a COVID-19 vaccine may be authorized for sale in Canada, based on an evaluation of the safety, efficacy and quality of that vaccine. There is no federal definition for a COVID-19 vaccine outside of what the product label describes, and as authorized by Health Canada.
Given the frequently changing context of COVID-19 variants of concern globally and the evolving science, which affects the understanding and measurement of immunity of individuals and population protection against COVID-19, including the variable and changing duration of immunity conferred by vaccination and infection-acquired immunity, the Government of Canada does not have a definition of herd immunity specific to COVID-19. The Canadian Immunization Guide, developed based on the recommendations and statements of expert advisory committees, including the National Advisory Committee on Immunization and the Committee to Advise on Tropical Medicine and Travel, refers to herd immunity in general for a number of viruses; it was developed prior to COVID-19 and is not specific to or directly applicable to COVID-19.
The Government of Canada’s definition for a fully vaccinated person entering Canada considers a traveller fully vaccinated if they have received at least two doses of a COVID-19 vaccine accepted for travel, a combination of accepted vaccines, or at least one dose of the Janssen/Johnson & Johnson vaccine, and have received a second dose at least 14 days before entering Canada. The government first established the definition of fully vaccinated as part of the quarantine, isolation and other obligations emergency order under the Quarantine Act in the context of border entry measures, to provide for a return to some degree of normalcy by facilitating the travel corridor for vaccinated travellers while retaining additional measures such as mandatory 14-day quarantine for unvaccinated travellers. The definition of a fully vaccinated person for border entry purposes into Canada came into force on July 5, 2021 and has not changed; it remains in effect until further notice.
In response to part (d) of the question, the Government of Canada’s national surveillance case definitions can be reviewed at www.canada.ca/en/public-health/services/diseases/2019-novel-coronavirus-infection/health-professionals/national-case-definition. The government uses standard definitions for confirmed, probable, reinfection, deceased and resolved cases of COVID-19. These national case definitions use the standard terminology of “case” for national surveillance of COVID-19; the case definitions do not refer to a definition for “sick person”, and this was not included in previous case definitions.
Concerning part (e) of the question, the cycle threshold value is specific to each test. It is established by the company that developed the test to ensure that the test performs accurately. Health Canada does not set recommended cycle thresholds and has not published specific guidance related to cycle thresholds.