Impact of a vaccine passport on first-dose COVID-19 vaccine coverage by age and area-level social determinants in the Canadian provinces of Québec and Ontario: an interrupted time series analysis

Background In Canada, all provinces implemented vaccine passports in 2021 to increase vaccine uptake and reduce transmission in non-essential indoor spaces. We evaluate the impact of vaccine passport policies on first-dose COVID-19 vaccination coverage by age, area-level income and proportion racialized. Methods We performed interrupted time-series analyses using vaccine registry data linked to census information in Québec and Ontario (20.5 million people ≥12 years; unit of analysis: dissemination area). We fit negative binomial regressions to weekly first-dose vaccination, using a natural spline to capture pre-announcement trends, adjusting for baseline vaccination coverage (start: July 3rd; end: October 23rd Québec, November 13th Ontario). We obtain counterfactual vaccination rates and coverage, and estimated vaccine passports’ impact on vaccination coverage (absolute) and new vaccinations (relative). Results In both provinces, pre-announcement first-dose vaccination coverage was 82% (≥12 years). The announcement resulted in estimated increases in vaccination coverage of 0.9 percentage points (p.p.;95%CI:0.4-1.2) in Québec and 0.7 p.p. (95%CI:0.5-0.8) in Ontario. In relative terms, these increases correspond to 23% (95%CI:10-36%) and 19% (95%CI:15-22%) more vaccinations. The impact was larger among people aged 12-39 (1-2 p.p.). There was little variability in the absolute impact by area-level income or proportion racialized in either province. Conclusions In the context of high baseline vaccine coverage across two provinces, the announcement of vaccine passports led to a small impact on first-dose coverage, with little impact on reducing economic and racial inequities in vaccine coverage. Findings suggest the need for other policies to further increase vaccination coverage among lower-income and more racialized neighbourhoods and communities. Key messages ### Competing Interest Statement DB reports past contractual agreements with Institut national d'excellence en santé et en services sociaux (INESSS). MB reports grants from: Canadian Institutes of Health Research (CIHR), Medical Research Council, UK (MRC), the Bill and Melinda Gates Foundation, the Centers for Disease Control and Prevention (CDC), FRSQ/FCAR health research, the World Health Organization (WHO), the Public Health Agency of Canada (PHAC), the Québec Ministry of Health and Social Services, and the Institut national de santé publique du Québec (INSPQ). MMG reports a research grant from Gilead Sciences Inc., contractual agreements with the WHO and the Joint United Nations Programme on HIV/AIDS, and past contractual agreements with INESSS and INSPQ. ### Funding Statement This study was funded by the Canadian Institutes of Health Research. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The IRB of the Faculty of Medicine and Health Sciences of McGill University in Québec gave ethical approval for this work (A06-M52-20B). The Health Sciences Research Ethics Board of the University of Toronto in Ontario gave ethical approval for this work (no. 39253). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The analysis code is available at https://github.com/pop-health-mod/vaccine-passport-release. The authors had access to data from the vaccination registries used in this study under agreements with the Institut national de santé publique du Québec and Ontario's Ministry of Health. These data are not available for public release. The census data used in this study can be downloaded from Statistics Canada at https://www150.statcan.gc.ca/n1/en/catalogue/98-316-X2016001.