Prevalence of SARS-CoV-2 infection among people experiencing homelessness in Toronto during the first wave of the COVID-19 pandemic
Linh Luong, Michaela Beder, Rosane Nisenbaum, Aaron Orkin, Jonathan P. Wong, Cynthia Damba, Ryan Emond, Suvendrini Lena, Vanessa Wright, Mona Loutfy, Cindy Bruce-Barrett, Wilfred Cheung, Yick Kan Cheung, Victoria Williams, Miriam Vanmeurs, Andrew Boozary, Harvey Manning, Joe Hester, Stephen W. Hwang
Abstract
OBJECTIVES: People experiencing homelessness are at increased risk of SARS-CoV-2 infection. This study reports the point prevalence of SARS-CoV-2 infection during testing conducted at sites serving people experiencing homelessness in Toronto during the first wave of the COVID-19 pandemic. We also explored the association between site characteristics and prevalence rates. METHODS: The study included individuals who were staying at shelters, encampments, COVID-19 physical distancing sites, and drop-in and respite sites and completed outreach-based testing for SARS-CoV-2 during the period April 17 to July 31, 2020. We examined test positivity rates over time and compared them to rates in the general population of Toronto. Negative binomial regression was used to examine the relationship between each shelter-level characteristic and SARS-CoV-2 positivity rates. We also compared the rates across 3 time periods (T1: April 17-April 25; T2: April 26-May 23; T3: May 24-June 25). RESULTS: The overall prevalence of SARS-CoV-2 infection was 8.5% (394/4657). Site-specific rates showed great heterogeneity with infection rates ranging from 0% to 70.6%. Compared to T1, positivity rates were 0.21 times lower (95% CI: 0.06-0.75) during T2 and 0.14 times lower (95% CI: 0.04-0.44) during T3. Most cases were detected during outbreak testing (384/394 [97.5%]) rather than active case finding. CONCLUSION: During the first wave of the pandemic, rates of SARS-CoV-2 infection at sites for people experiencing homelessness in Toronto varied significantly over time. The observation of lower rates at certain sites may be attributable to overall time trends, expansion of outreach-based testing to include sites without known outbreaks, and/or individual site characteristics.