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 3 rd ; end: October 23 rd Québec, November 13 th 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 Vaccine passport policies increased COVID-19 vaccination coverage by approximately 1 percentage point (19 to 23% increase in vaccinations) in Québec and Ontario, Canada. Although vaccine passport policies increased vaccination coverage, absolute gains were limited in the context of high prior vaccine coverage. Vaccine passports had little impact on reducing economic and racial inequities in vaccine coverage.