COVID-19 vaccine effectiveness among South Asians in Canada.

We evaluated the effectiveness of COVID-19 vaccines among South Asians living in Ontario, Canada compared to non-South Asians and compared the odds of symptomatic COVID-19 infection and related hospitalizations and deaths among non-vaccinated South Asians and non-South Asians. This was a test negative design study conducted in Ontario, Canada between December 14, 2020 and November 15, 2021. All eligible individuals >18 years with symptoms of COVID-19 were subdivided by ethnicity (South Asian vs other) and vaccination status (vaccinated versus not). The primary outcome was vaccine effectiveness as defined by COVID-19 infections, hospitalizations, and deaths, and secondary outcome was the odds of COVID-19 infections, hospitalizations, and death comparing non-vaccinated South Asians to non-vaccinated non-South Asians. 883,155 individuals were included. Among South Asians, two doses of COVID-19 vaccine prevented 93.8% (95% CI 93.2, 94.4) of COVID-19 infections and 97.5% (95% CI 95.2, 98.6) of hospitalizations and deaths. Among non-South Asians, vaccines prevented 86.6% (CI 86.3, 86.9) of COVID-19 infections and 93.1% (CI 92.2, 93.8) of hospitalizations and deaths. Non-vaccinated South Asians had higher odds of symptomatic SARS-CoV-2 infection compared to non-vaccinated non-South Asians (OR 2.35, 95% CI 2.3, 2.4), regardless of their immigration status. COVID-19 vaccines are effective in preventing infections, hospitalizations and deaths among South Asians living in Canada. The observation that non-vaccinated South Asians have higher odds of symptomatic COVID-19 infection warrants further investigation.

Copyright: © 2024 Chanchlani et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

The authors have read the journal’s policy and have the following competing interests: SSA holds a Tier 1 Canada Research Chair in Ethnic Diversity and Cardiovascular Disease (#CRC-2017-00024), and the Michael G DeGroote Heart and Stroke Foundation of Canada Chair in Population Health Research outside of the submitted work. ML sits on vaccine advisory boards for Seqirus, Pfizer, Sanofi, Medicago, GSK, Merck, Novovax, and Janssen; is on the Data Safety Monitoring Board for CanSino Biologics, has received funding from Seqirus for a vaccine trial, is receiving in-kind supply of smallpox vaccines from Bavarian Nordic, and has provided expert testimony about vaccines outside of the submitted work. DMEB holds a Tier 2 Canada Research Chair in Aging and Immunity, sits on vaccine advisory boards for Pfizer and AstraZeneca, has received consulting fees/honoraria for Pfizer and AstraZeneca, and has provided expert testimony about vaccines outside of the submitted work. SB is the Director of the Centre for Vaccine Preventable Diseases (CVPD) at the University of Toronto outside of the submitted work. The CVPD receives operational support from a mix of funding sources, including through donations from pharmaceutical companies. A robust set of governance practices are in place to safeguard the academic freedom of the CVPD. BRS is funded by the University of Toronto as the Novo Nordisk Research Chair in Equitable Care of Diabetes and Related Conditions outside of the submitted work. DS holds the Heather M. Arthur Population Health Research Institute/Hamilton Health Sciences Chair in Inter-Professional Health Research and has received an honorarium from Diabetes Update 2023 for being an invited speaker and is a co-methods lead on the Diabetes Canada Clinical Practice Guidelines Steering Committee outside of the submitted work. GW has received grants from the Canadian Institutes of Health Research and the Hamilton Health Sciences Foundation outside of the submitted work. RJdS has received grants from the Canadian Institutes of Health Research, Canadian Foundation for Dietetic Research, Population Health Research Institute, and Hamilton Health Sciences Corporation; he has received consulting fees and travel honoraria from the World Health Organization’s Nutrition Guidelines Advisory Group; he is an Independent Director for the Helderleigh Foundation (Canada) and Co-Chair of a method working group for the ADA/EASD Precision Medicine in Diabetes group outside of the submitted work. SIB has received grants from the Canadian Institutes of Health Research and from the International Development Research Centre; he also served as a member of the US National Institute of Allergy and Infectious Diseases Data and Safety Monitoring Board for COVID-19 Preventive monoclonal antibodies trials outside of the submitted work. All other authors declare that they have no competing interests. This does not alter our adherence to PLOS policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.