Seroprevalence of SARS-CoV-2 among African Canadians: Clinical and Epidemiological Correlates [seroMARK, study data contributed to the CITF Databank]

<b> Background:</b> Preliminary data suggested Black Canadians were disproportionately represented among COVID-19 cases and severe outcomes, including death. <br>
<b> Aims of study: </b> This study aimed to determine the seroprevalence of SARS-CoV-2 infection among a population of black Canadians residing in geographic areas of Ontario with high rates of COVID-19 in order to determine the extent to which this population is vulnerable to COVID-19 or future waves of infection. They also aimed to study the risk factors for infection, and the relationship between serological evidence of infection and neutralizing antibodies, and their sustainability. <br>
<b> Methods: </b> This cross-sectional study enrolled black Canadians and non-Black Canadians as controls across Ontario. Serum samples were collected to measure SARS-CoV-2 antibodies, and repeat samples were collected and measured for those who tested positive for SARS-CoV-2 antibodies. Additionally, data on work, housing, socioeconomic status, and pre-existing conditions were collected to support a comprehensive analysis of risk factors. <br>
<b> Contributed dataset contents: </b> The datasets include 216 participants from Toronto who completed the baseline survey between March 2022 and July 2024. 74 participants (35%) continued follow-up surveys, and 4 new participants were recruited during the follow-up stage (contributed one or more times of follow-up visit). All participants (220) gave one or more serology samples. A total of 314 samples were collected between October 2020 and July 2024. <br>
For London area, the datasets include 72 participants who completed survey, and all participants gave one serology sample between December 2020 and February 2023. <br>
Variables include data in the following areas of information: demographics (age, gender, race-ethnicity, occupation), general health (lung disease, heart disease, immunosuppression, height and weight, flu vaccine), longitudinal follow up for COVID infection (test date and result, hospitalization), SARS-CoV-2 vaccination and serology.

**背景：** 初步研究数据表明，加拿大黑人群体在新冠病毒（SARS-CoV-2）感染病例及包括死亡在内的重症结局中占比失衡。
**研究目的：** 本研究旨在针对安大略省新冠感染率较高的地理区域内居住的加拿大黑人群体，开展新冠病毒血清阳性率调查，以明确该群体感染新冠病毒或遭遇未来疫情浪潮时的易感程度；同时探究新冠感染相关危险因素，以及感染血清学证据与中和抗体的关联及其持久性。
**研究方法：** 本项横断面研究在安大略省招募加拿大黑人作为研究对象，并纳入非黑人加拿大人群作为对照。研究人员采集血清样本以检测新冠病毒抗体，对于新冠病毒抗体检测呈阳性的受试者，额外采集并检测其随访血清样本。此外，研究收集了受试者的工作、住房、社会经济状况及基础疾病相关数据，以支持危险因素的全面分析。
**数据集贡献内容：** 多伦多队列数据集包含来自多伦多地区、于2022年3月至2024年7月间完成基线调查的216名受试者。其中74名受试者（占比35%）完成了后续随访调查，另有4名受试者在随访阶段被招募入组，且贡献了一次或多次随访访视数据。所有受试者（共计220人）均提供了一次或多次血清学样本，2020年10月至2024年7月间共采集血清样本314份。
伦敦地区数据集包含72名完成调查的受试者，所有受试者均在2020年12月至2023年2月间提供了一份血清学样本。
数据集变量涵盖以下几类信息：人口统计学数据（年龄、性别、种族族裔、职业）、一般健康状况（肺部疾病、心脏病、免疫抑制状态、身高体重、流感疫苗接种情况）、新冠感染纵向随访数据（检测日期与结果、住院情况）、新冠病毒疫苗接种及血清学检测相关信息。