Cohort Profile: Prospective Cohort to Study the COVID-19 Immune Response in Retail Workers in Québec, Canada (CISACOV)

Purpose Retail workers are an understudied occupational group that may have been at increased risk of contracting SARS-CoV-2 during the COVID-19 pandemic. Therefore, we set up a longitudinal cohort of participants working in this sector to better document the incidence of SARS-CoV-2 infection and the immune response to infection and/or vaccination in this group. Participants A total of 304 participants were recruited between April 20, 2021 and October 22, 2021. They were invited to attend three visits (each separated by ∼12 weeks) during which they provided blood samples and information on participant characteristics, COVID-19 symptoms, and vaccination. An extension phase of two additional visits was carried out between March 15th, 2022 and October 3rd, 2022 to document the impact of the Omicron variant among the 198 participants who were still eligible for recruitment. Participants were aged 18 to 75 and worked in grocery stores, hardware stores, bars or restaurants within the Québec City metropolitan area (Canada). Findings to date: This article describes participants’ demographic, socioeconomic, behavioral, clinical and occupational characteristics, and their COVID-19 symptoms (where applicable). It also describes SARS-CoV-2 vaccination status and any SARS-CoV-2 diagnostic test (i.e., PCR or rapid antigen) performed from the beginning of the pandemic until the last visit. Future plans The incidence of SARS-CoV-2 infections will be assessed. The immune response (innate and acquired) to SARS-CoV-2 infection or vaccination will be studied using a variety of techniques, including reference and experimental enzyme-linked immunosorbent assays, microneutralization assays with live viruses, experimental pseudoneutralization with an angiotensin-converting enzyme 2-spike assay, peripheral blood mononuclear cells and neutrophil stimulation, and a proliferation assay based on carboxyfluorescein diacetate succinimidyl ester. Registration Not applicable. Strengths and limitations ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This project is being supported by funding from the Public Health Agency of Canada, through the Vaccine Surveillance Reference group and the COVID-19 Immunity Task Force (grant number: 2021-HQ-000134). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee/IRB of the CHU de Quebec Research Center gave ethical approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors All data produced are available online at the COVID-19 Immunity Task Force (CITF) Data Portal