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Review
. 2022 Sep:4:157-164.
doi: 10.1016/j.ijregi.2022.07.010. Epub 2022 Jul 29.

Systematic literature review of SARS-CoV-2 seroprevalence surveys in Canada through April 2021

Maria Major  1   2 , Shannon E Majowicz  1 , Mark Oremus  1 , Laura Juliana Jimenez  1 , Frederick J Angulo  3 , Susan Horton  1
Affiliations
Review

Systematic literature review of SARS-CoV-2 seroprevalence surveys in Canada through April 2021

Maria Major et al. IJID Reg. 2022 Sep.

Abstract

Objectives: To estimate the proportion of the population infected by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in Canada through April 2021, 16 months into the coronavirus disease 2019 (COVID-19) pandemic and 4 months after COVID-19 vaccines became available.

Methods: Publication databases, preprint servers, public health databases and the grey literature were searched for seroprevalence surveys conducted in Canada from 1 November 2019 to 10 July 2021. Studies were assessed for bias using the Joanna Briggs Checklist. Numbers of infections derived from seroprevalence estimates were compared with reported cases to estimate under-ascertainment ratios.

Results: In total, 12 serosurveys with 210,321 participants were identified. Three (25%) serosurveys were conducted at national level, one (8.3%) was conducted at provincial level, and eight (66.7%) were conducted at local level. All 12 serosurveys had moderate or high risk of bias. The proportion of the population infected by April 2021 was low (2.6%). The proportion of the population infected was higher in surveys of residents of long-term care facilities (43.0-86%), workers at long-term care facilities (22.4-32.4%), and workers in healthcare institutions (1.4-14%).

Conclusions: As of April 2021, the proportion of the population infected by SARS-CoV-2 was low in the overall population of Canada, but was high in healthcare facilities, particularly long-term care facilities, supporting the need for vaccines.

Keywords: Antibodies; COVID-19; Canada; SARS-CoV-2; Seroprevalence; Serosurvey.

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Figures

Figure 1
Figure 1
Trends in cases of coronavirus disease 2010 in Canada (31 January 2020–10 July 2021).
Figure 2
Figure 2
PRISMA flowchart. From: Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372:n71.
Figure 3
Figure 3
Risk-of-bias assessment of the 12 severe acute respiratory syndrome coronavirus-2 serosurveys in Canada from March 2020 to April 2021.
See this image and copyright information in PMC

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