Alberta Childhood COVID-19 Cohort [AB3C, study data contributed to the CITF Databank]

<b>Background</b>: Given the novel SARS-CoV-2 coronavirus pandemic, there was a need to understand COVID-19 in Alberta children to inform potential treatments, vaccines, and public safety decisions such as when and how children should return to school. This study was not funded by the CITF; Dr. Kellner, as co-chair of the CITF Field Studies and Pediatric working groups, helped design the CITF Core Data Elements and questionnaires. <br><br>
<b>Aims of the original study</b>: The AB3C study aimed to determine how many children with and without known COVID-19 infections have made an immune response (blood antibodies) over time, and the epidemiologic and immunological correlates of infection risk and COVID disease severity. <br><br>
<b>Methods</b>: Parents were invited to enroll their child (less that 18 years) in the study if they lived in or near Calgary, AB. They were enrolled as single-visit or longitudinal participants. In addition to questionnaire items, at each visit (6 months apart) past COVID infection status was ascertained (priority to PCR result) and a blood sample drawn for serology. IgG antibodies to SARS-CoV-2 nucleocapsid protein and receptor binding domain of the spike were measured. <br><br>
<b>Summary of the contributed data</b>: The dataset includes 1030 participants who completed a baseline visit between August and November 2020 and provided at least one blood sample. 94% of participants were followed longitudinally up to 2 years (median: 19 months). Available variables include data for the following areas of information: demographics (age, sex, race-ethnicity and indigeneity, FSA), chronic health conditions, and BMI at baseline; acute COVID infection evidence, SARS-CoV-2 vaccination, and serology over time.

<b>研究背景</b>：鉴于新型严重急性呼吸综合征冠状病毒2型（SARS-CoV-2）大流行，亟需明确阿尔伯塔省儿童的新型冠状病毒肺炎（COVID-19）流行特征，以为潜在治疗方案、疫苗研发及儿童返校时机与方式等公共卫生安全决策提供科学依据。本研究未获CITF资助；凯尔纳博士作为CITF现场研究与儿科工作组联合主席，协助设计了CITF核心数据要素与调查问卷。

<b>原始研究目标</b>：AB3C研究旨在探明，无论是否存在明确的新冠病毒感染史，有多少儿童随时间推移产生了免疫应答（血液抗体），同时明确感染风险与新冠病情严重程度的流行病学及免疫学关联因素。

<b>研究方法</b>：凡居住在阿尔伯塔省卡尔加里市内或周边地区的家长，均可受邀为其18岁以下子女报名参与本研究。参与者分为单次随访与纵向随访两类。除调查问卷采集的信息外，每次随访（间隔6个月）均会确认受试者既往新冠感染史（优先参考聚合酶链式反应（PCR）检测结果），并采集血液样本用于血清学检测。本研究同时检测了针对SARS-CoV-2核衣壳蛋白与刺突蛋白受体结合域的免疫球蛋白G（IgG）抗体水平。

<b>数据集内容概述</b>：本数据集共纳入1030名参与者，他们均于2020年8月至11月完成基线随访，并提供了至少一份血液样本。其中94%的参与者接受了最长达2年的纵向随访（中位随访时长：19个月）。可用变量涵盖以下几类信息：基线时的人口统计学信息（年龄、性别、种族族裔与原住民身份、FSA）、慢性健康状况与体重指数（BMI）；急性新冠感染证据、SARS-CoV-2疫苗接种情况，以及随时间变化的血清学检测结果。