Impact of a vaccine passport on first-dose SARS-CoV-2 vaccine coverage by age and area-level social determinants of health in the Canadian provinces of Quebec and Ontario: an interrupted time series analysis

Jorge Luis Flores Anato; Huiting Ma; Mackenzie A Hamilton; Yiqing Xia; Sam Harper; David Buckeridge; Marc Brisson; Michael P Hillmer; Kamil Malikov; Aidin Kerem; Reed Beall; Caroline E Wagner; Étienne Racine; Stefan Baral; Ève Dubé; Sharmistha Mishra; Mathieu Maheu-Giroux

doi:10.9778/cmajo.20220242

Impact of a vaccine passport on first-dose SARS-CoV-2 vaccine coverage by age and area-level social determinants of health in the Canadian provinces of Quebec and Ontario: an interrupted time series analysis

CMAJ Open. 2023 Oct 24;11(5):E995-E1005. doi: 10.9778/cmajo.20220242. Print 2023 Sep-Oct.

Authors

Jorge Luis Flores Anato¹, Huiting Ma¹, Mackenzie A Hamilton¹, Yiqing Xia¹, Sam Harper¹, David Buckeridge¹, Marc Brisson¹, Michael P Hillmer¹, Kamil Malikov¹, Aidin Kerem¹, Reed Beall¹, Caroline E Wagner¹, Étienne Racine¹, Stefan Baral¹, Ève Dubé¹, Sharmistha Mishra¹, Mathieu Maheu-Giroux²

Affiliations

¹ Department of Epidemiology and Biostatistics (Flores Anato, Xia, Harper, Buckeridge, Racine, Maheu-Giroux), School of Population and Global Health, McGill University, Montréal, Que.; MAP Centre for Urban Health Solutions (Ma, Hamilton, Mishra), St. Michael's Hospital, Unity Health Toronto, Toronto, Ont.; Centre de Recherche du CHU de Québec and Département de médecine sociale et préventive (Brisson), Université Laval, Québec, Que.; Ontario Ministry of Health (Hillmer, Malikov, Kerem); Institute of Health Policy, Management and Evaluation (Hillmer), University of Toronto, Toronto, Ont.; Department of Community Health Sciences (Beall), Cumming School of Medicine, University of Calgary, Calgary, Alta.; Department of Bioengineering (Wagner), McGill University, Montréal, Que.; Direction des risques biologiques (Racine, Dubé), Institut national de santé publique du Québec, Ville de Québec, Que.; Department of Epidemiology (Baral), Johns Hopkins School of Public Health, Baltimore, Md.; Département d'anthropologie (Dubé), Faculté des sciences sociales, Université Laval, Québec, Que.; Division of Infectious Diseases, Department of Medicine (Mishra), University of Toronto, Toronto, Ont.
² Department of Epidemiology and Biostatistics (Flores Anato, Xia, Harper, Buckeridge, Racine, Maheu-Giroux), School of Population and Global Health, McGill University, Montréal, Que.; MAP Centre for Urban Health Solutions (Ma, Hamilton, Mishra), St. Michael's Hospital, Unity Health Toronto, Toronto, Ont.; Centre de Recherche du CHU de Québec and Département de médecine sociale et préventive (Brisson), Université Laval, Québec, Que.; Ontario Ministry of Health (Hillmer, Malikov, Kerem); Institute of Health Policy, Management and Evaluation (Hillmer), University of Toronto, Toronto, Ont.; Department of Community Health Sciences (Beall), Cumming School of Medicine, University of Calgary, Calgary, Alta.; Department of Bioengineering (Wagner), McGill University, Montréal, Que.; Direction des risques biologiques (Racine, Dubé), Institut national de santé publique du Québec, Ville de Québec, Que.; Department of Epidemiology (Baral), Johns Hopkins School of Public Health, Baltimore, Md.; Département d'anthropologie (Dubé), Faculté des sciences sociales, Université Laval, Québec, Que.; Division of Infectious Diseases, Department of Medicine (Mishra), University of Toronto, Toronto, Ont. mathieu.maheu-giroux@mcgill.ca.

Abstract

Background: In Canada, all provinces implemented vaccine passports in 2021 to reduce SARS-CoV-2 transmission in non-essential indoor spaces and increase vaccine uptake (policies active September 2021-March 2022 in Quebec and Ontario). We sought to evaluate the impact of vaccine passport policies on first-dose SARS-CoV-2 vaccination coverage by age, and area-level income and proportion of racialized residents.

Methods: We performed interrupted time series analyses using data from Quebec's and Ontario's vaccine registries linked to census information (population of 20.5 million people aged ≥ 12 yr; unit of analysis: dissemination area). We fit negative binomial regressions to first-dose vaccinations, using natural splines adjusting for baseline vaccination coverage (start: July 2021; end: October 2021 for Quebec, November 2021 for Ontario). We obtained counterfactual vaccination rates and coverage, and estimated the absolute and relative impacts of vaccine passports.

Results: In both provinces, first-dose vaccination coverage before the announcement of vaccine passports was 82% (age ≥ 12 yr). The announcement resulted in estimated increases in coverage of 0.9 percentage points (95% confidence interval [CI] 0.4-1.2) in Quebec and 0.7 percentage points (95% CI 0.5-0.8) in Ontario. This corresponds to 23% (95% CI 10%-36%) and 19% (95% CI 15%-22%) more vaccinations over 11 weeks. The impact was larger among people aged 12-39 years. Despite lower coverage in lower-income and more-racialized areas, there was little variability in the absolute impact by area-level income or proportion racialized in either province.

Interpretation: In the context of high vaccine coverage across 2 provinces, the announcement of vaccine passports had a small impact on first-dose coverage, with little impact on reducing economic and racial inequities in vaccine coverage. Findings suggest that other policies are needed to improve vaccination coverage among lower-income and racialized neighbourhoods and communities.