COVID-19 vaccine equity: a retrospective population-based cohort study examining primary series and first booster coverage among persons with a history of immigration and other residents of Ontario, Canada

Abstract

IntroductionImmigrants were disproportionately impacted by COVID-19 and experience unique vaccination barriers. In Canada (37 million people), 23% of the population is foreign-born. Immigrants constitute 60% of the country’s racialized (non-white) population and over half of immigrants reside in Ontario, the country’s most populous province. Ontario had several strategies aimed at improving vaccine equity including geographic targeting of vaccine supply and clinics, as well as numerous community-led efforts. Our objectives were to (1) compare primary series vaccine coverage after it was widely available, and first booster coverage 6 months after its availability, between immigrants and other Ontario residents and (2) identify subgroups experiencing low coverage.Materials and methodsUsing linked immigration and health administrative data, we conducted a retrospective population-based cohort study including all community-dwelling adults in Ontario, Canada as of January 1, 2021. We compared primary series (two-dose) vaccine coverage by September 2021, and first booster (three-dose) coverage by March 2022 among immigrants and other Ontarians, and across sociodemographic and immigration characteristics. We used multivariable log-binomial regression to estimate adjusted risk ratios (aRR).ResultsOf 11,844,221 adults, 22% were immigrants. By September 2021, 72.6% of immigrants received two doses (vs. 76.4%, other Ontarians) and by March 2022 46.1% received three doses (vs. 58.2%). Across characteristics, two-dose coverage was similar or slightly lower, while three-dose coverage was much lower, among immigrants compared to other Ontarians. Across neighborhood SARS-CoV-2 risk deciles, differences in two-dose coverage were smaller in higher risk deciles and larger in the lower risk deciles; with larger differences across all deciles for three-dose coverage. Compared to other Ontarians, immigrants from Central Africa had the lowest two-dose (aRR = 0.60 [95% CI 0.58–0.61]) and three-dose coverage (aRR = 0.36 [95% CI 0.34–0.37]) followed by Eastern Europeans and Caribbeans, while Southeast Asians were more likely to receive both doses. Compared to economic immigrants, resettled refugees and successful asylum-claimants had the lowest three-dose coverage (aRR = 0.68 [95% CI 0.68–0.68] and aRR = 0.78 [95% CI 0.77–0.78], respectively).ConclusionTwo dose coverage was more equitable than 3. Differences by immigrant region of birth were substantial. Community-engaged approaches should be re-invigorated to close gaps and promote the bivalent booster.

COVID-19 hospitalization, mortality and premature mortality by a history of immigration in Ontario, Canada: a population-based cohort study

“…After these East Asian regions, immigrants from Europe and North America/Australasia/Oceania had the lowest adjusted rate ratios. Relative to our third aim, high COVID-19 primary series vaccine coverage in Ontario 25 appeared to dramatically reduce the inequities experienced in the pre-vaccine era cohort. Hospitalization and mortality rate ratios dropped substantially for all immigration categories, except refugees, to rates similar to or lower than other Ontarians.…”

“…We found equitable primary series coverage among adult immigrants and other Ontario residents (72.6% vs. 76.4%, respectively) as of Sept 2021 with substantially lower coverage among immigrants from only a handful of regions of birth (i.e., Central Africa, Eastern Europe, the Caribbean). 25 The success of the primary series vaccine campaign in Ontario can be attributed to a number of factors, including a policy to prioritize vaccine distribution to high-risk neighborhoods, public health efforts to use data to guide equitable vaccination strategies, and numerous culturally appropriate community-led vaccination efforts. These successes demonstrate that immense challenges can be overcome when community needs and equity are both prioritized and adequately supported.…”

“…Despite the World Health Organization declaring the COVID-19 pandemic over recently (May 2023), most studies on severe outcomes among immigrants include data from only the first wave and do not overlap with the availability of COVID-19 vaccines, limiting our understanding of the cumulative impact of these outcomes among immigrants, and whether vaccines mitigated these impacts. We recently demonstrated 25 that immigrants overall had similar two-dose COVID-19 vaccine coverage as other residents of Ontario with some significant variability by region of birth, but much lower three-dose coverage overall and across almost all regions of birth. It is unclear how COVID-19 severe outcomes among immigrants in Canada or elsewhere were impacted by COVID-19 vaccine coverage.…”