Seroprevalence and Risk Factors for SARS-CoV-2 Among Incarcerated Adult Men in Quebec, Canada (2021): A Cross-Sectional Study

Abstract

Background: People in prison are at increased risk of SARS-CoV-2 infection due to overcrowding and challenges in implementing infection prevention and control measures. We examined the seroprevalence of SARS-CoV-2 and associated risk factors among incarcerated adult men in Quebec, Canada.

Methods: We conducted a cross-sectional seroprevalence study in 2021 in three provincial prisons, representing 45% of Quebec’s incarcerated male provincial population. The primary outcome was SARS-CoV-2 antibody seropositivity (Roche Elecsys® serology test). Participants completed self-administered questionnaires on sociodemographic, clinical, and carceral characteristics. The association of carceral variables with SARS-CoV-2 seropositivity was examined using Poisson regression models with robust standard errors. Crude and adjusted prevalence ratios (aPR) with 95% confidence intervals (95%CI) were calculated.

Findings: Between January 19 and September 15, 2021, 246 of 1,100 (22%) recruited individuals tested positive across three prisons (range 15–27%). Seropositivity increased with time spent in prison since March 2020 (aPR 2·17, 95%CI 1·53–3·07 for “all” vs. “little time”), employment during incarceration (aPR 1·64, 95%CI 1·28–2·11 vs. not), shared meal consumption during incarceration (“with cellmates”: aPR 1·46, 95%CI 1·08–1.97 vs. “alone”; “with sector”: aPR 1·34, 95%CI 1·03–1·74 vs. “alone”), and incarceration post-prison outbreak (aPR 2·32, 95% CI 1·69–3·18 vs. “pre-outbreak”).

Interpretation: The seroprevalence of SARS-CoV-2 among incarcerated individuals was high and varied between prisons. Several carceral factors were associated with seropositivity, underscoring the importance of decarceration and occupational safety measures, individual meal consumption, and enhanced infection prevention and control measures including vaccination during incarceration.

Funding Information: The Public Health Agency of Canada funded this study (# 2021-HQ-000103).

Declaration of Interests: CD, AH, SC, JS, HP, LDB, and SP declare no competing interests. NK reports research funding from Gilead Sciences, advisory fees from Gilead Sciences, ViiV Healthcare, Merck and Abbvie, and speaker fees from Gilead Sciences and Merck, all outside of the submitted work. MMG reports an investigator-sponsored research grant from Gilead Sciences Inc. MMG reports contractual arrangements with the World Health Organization, the Institut national de santé publique du Québec, and the Institut d’excellence en santé et services sociaux du Québec, all outside of the submitted work. MPC reports grants from the McGill Interdisciplinary Initiative in Infection and Immunity and from the Canadian Institutes of Health Research. MPC reports personal fees from GEn1E Lifesciences and form nplex biosciences, both outside the submitted work. MPC is the co-founder of Kanvas Biosciences, Inc. and owns equity in the company. MPC has a pending patent for Methods for detecting tissue damage, graft versus host disease, and infections using cell-free DNA profiling pending, and a pending patent for Methods for assessing the severity and progression of SARS-CoV-2 infections using cell-free DNA. JC has research funding from ViiV Healthcare and Gilead Sciences, and reports remuneration for advisory work (ViiV Healthcare, Gilead Sciences and Merck Canada), outside the submitted work.

Ethics Approval Statement: Participants provided written informed consent and received an honorarium of $10 CAD for their study participation. This study was approved by the McGill University Health Centre Research Ethics Board (MUHC REB #2021–6888) and the Direction régionale des services correctionnels du Québec (#2020–12493).

Keywords: SARS-CoV-2, COVID-19, Seroprevalence, Antibody, Prison, People who are incarcerated.