PDF file: 451-0849_Why_PHAC_counted_Cases_following_vaccination_starting_from_14_DEC_2020_April_13.pdf
OPQ ID: 451-0849
Session: 451
Question number: Q-0849
Sessional paper: 8555-451-849
Title: Why PHAC counted Cases following vaccination starting from 14 DEC 2020, April 13, 2026
Short description: 
Topic: vaccines
Identified concern: 
Keywords: 
Agencies: HC, PHAC, StatCan
Date asked: 2026-02-09
Date tabled: 2026-04-13
Submitted by: Dean Allison (Niagara West)
Reply by: the Minister of Health
Responded by: Maggie Chi
Pages: 4
Status: not processed
Alert: red
Questions asked: 6
Questions answered: 
Percent responded: 0%
Referenced sources: World Health Organization, Centers for Disease Control, Field Epidemiology Manual, COVID-19 Epidemiology and Modelling Presentations
Referenced links: (none extracted)
Official link: https://www.google.com/search?q=8555-451-849+ourcommons.ca
PDF URL: https://ivim.ca/foi/opq/r/451-0849_Why_PHAC_counted_Cases_following_vaccination_starting_from_14_DEC_2020_April_13.pdf
TXT URL: https://ivim.ca/foi/opq/r/451-0849.txt
Original filename: Q-849 - Why PHAC counted Cases following vaccination starting from 14 DEC 2020, April 13, 2026.pdf
Local source path: C:\Users\Dmitry\Documents\CODES\OPQ-App\data-raw\OPQ\ALL OPQ TO DATE\2025\Q-849 - Why PHAC counted Cases following vaccination starting from 14 DEC 2020, April 13, 2026.pdf
Machine extracted at: 2026-06-30 12:58:32

References / links:
- World Health Organization
- Centers for Disease Control
- Field Epidemiology Manual
- COVID-19 Epidemiology and Modelling Presentations

Machine notes:
(none)

Question text preview:
With regard to the Public Health Agency of Canada’s “Cases Following Vaccination” reports published from August 2021 to
September 2022: (a) why did the Public Health Agency of Canada decide to begin calculating and comparing COVID-19 deaths using vaccination status, on the date of COVID-19 vaccine approval in December 2020, rather than the date on which each corresponding dose level actually began to be administered, or using weekly death counts, as is done for Statistics Canada’s
Deaths by Age and Deaths by cause statistics;
(b) what internal documentation, analyses, and external scientific or technical references were consulted to inform the methodological choice described in (a);
(c) within the Public Health Agency of
Canada, which organizational units and officials or governing authorities (i) proposed the methodology described in (a), (ii) reviewed it (including any internal methodological or ethics review), (iii) formally approved it for use in the “Cases Following
Vaccination” reports;
(d) in what way does the methodology described in (a) permit the observation and analysis of timebased (for example, weekly or seasonal) variations in COVID-19 deaths by vaccination status in relation to contemporaneous factors, including, but not limited to, seasonal changes and the dates on which additional vaccine doses (for example, second, third, or booster doses) began to be administered; and (e) in developing and approving this methodology, did the Public Health
Agency of Canada rely on, or explicitly reference, any guidance, standards, or methodologies issued by the World Health
Organization or any other international public health body, and, if so, which specific documents or authorities were relied upon?
Response
This response was tabled in the House of Commons on April 13, 2026, as Sessional Paper 8555-451-849.
Order/Address of the House of Commons
Question number
Q-849
Asked by
Dean Allison (Niagara West)
Date asked
February 9, 2026
Tabled on
April 13, 2026
Sessional Paper
8555-451-849
House of Commons
Health Canada
Reply by: the Minister of Health
Name of Signatory: Maggie Chi
Reply
Public Health Agency of Canada
(a) why did the Public Health Agency of Canada decide to begin calculating and comparing COVID-19 deaths using vaccination status, on the date of COVID-19 vaccine approval in December 2020, rather than the date on which each corresponding dose level actually began to be administered, or using weekly death counts, as is done for
Statistics Canada’s Deaths by Age and Deaths by cause statistics?
The cumulative number of cases by vaccination status were presented in the Public Health Agency of Canada’s “Cases following vaccination” section of the COVID-19 daily epidemiology update from the date of vaccine approval because
COVID-19 vaccine rollout varied by province/territory.
In many provinces/territories, individuals received two doses within a month of vaccine approval, and the date of approval provided a clear and consistent starting point for monitoring these cases by vaccination status over time.
Weekly death counts by vaccination status group were low for many weeks so death counts were not presented in this manner due to privacy concerns.
(b) what internal documentation, analyses, and external scientific or technical references were consulted to inform the methodological choice described in (a)?
The Public Health Agency of Canada’s methodology for describing COVID‑19 cases by vaccination status follows standard, foundational principles of descriptive epidemiology, as outlined in the World Health Organization’s Critical preparedness, readiness and response actions for COVID-19 and the Centers for Disease Control’s Field Epidemiology Manual.
These resources recommend characterizing health events by person, place, and time to identify patterns, generate hypotheses, and guide public health action.
The Public Health Agency of Canada applied these internationally recognized methods to
Presented by
Sherry Romanado
Parliamentary Secretary to the
Minister of National Defence
stratify cases by vaccination status, which is consistent with standard surveillance practice; this descriptive approach does not, on its own, determine causation or vaccine effectiveness.
With respect to internal documentation, the Public Health Agency of Canada follows foundational principles of descriptive epidemiology well described elsewhere (e.g., various epidemiology textbooks) and knowledge of epidemiologic methods is a key qualification for epidemiologists who prepare these reports.
However, the COVID-19 Epidemiology and Surveillance
Division responsible for these analyses was guided by the World Health Organization’s Critical preparedness, readiness and response actions for COVID-19 and the Centers for Disease Control’s Field Epidemiology Manual and did follow the
Division’s routine methodological processes which include the development of an analytic plan to describe the data sources, case definitions, methodological steps, and planned outputs.
This analytic plan was reviewed and approved as outlined in response (c) below.
(c) within the Public Health Agency of Canada, which organizational units and officials or governing authorities (i) proposed the methodology described in (a), (ii) reviewed it (including any internal methodological or ethics review), (iii) formally approved it for use in the “Cases Following Vaccination” reports?
The COVID-19 Epidemiology and Surveillance Division within the Centre for Emerging Respiratory Infections and
Pandemic Preparedness, of the Infectious Disease and Vaccination Programs Branch was responsible for surveillance of
COVID-19, including the description of COVID-19 cases by vaccination status.
Internal consultations on analytic methods and approach to visualization (i.e., format of graphs and tables) occurred before the first public dissemination, and the analytic approach was routinely re-evaluated and adjusted as required (i.e., as the vaccine roll-out continued and additional doses were added to the series).
Review and approval for methods and surveillance reporting followed routine accountability processes for this type of product which was approval by the Director of the COVID-19 Epidemiology and
Surveillance Division.
The Public Health Agency of Canada research and ethics board review was not required as the descriptive analysis of cases following vaccination is considered standard public health surveillance practice and not research.
(d) in what way does the methodology described in (a) permit the observation and analysis of time-based (for example, weekly or seasonal) variations in COVID-19 deaths by vaccination status in relation to contemporaneous factors, including, but not limited to, seasonal changes and the dates on which additional vaccine doses (for example, second, third, or booster doses) began to be administered?
In the Cases Following Vaccination report, the weekly incidence of COVID-19 deaths was compared amongst vaccination status groups, presented as an age-standardized incidence rate ratio.
This measure incorporated the number of individuals in each vaccination status group, accounting for when each corresponding dose was administered, and alleviating privacy concerns discussed in (a).
Results of this analysis were also publicly published in Statements from the Chief Public Health
Officer of Canada and COVID-19 Epidemiology and Modelling Presentations.
Other analyses and reports were prepared and disseminated to accomplish similar objectives, including the Public Health Agency of Canada’s COVID‑19 Cases
Following Vaccination Weekly Epidemiology Report, which presented the weekly incidence of COVID‑19 cases and hospitalizations by vaccination status, and a peer-reviewed analysis of the association of COVID‑19 vaccination and incidence of COVID‑19 cases in Canada, assessing the probability of COVID‑19 illness by vaccination status, controlling for a number of potential confounders.
(e) in developing and