Center for Genetic Medicine and.
Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
JCI Insight. 2021 May 10;6(9):146148. doi: 10.1172/jci.insight.146148.
BACKGROUNDEstimates of seroprevalence to SARS-CoV-2 vary widely and may influence vaccination response. We ascertained IgG levels across a single US metropolitan site, Chicago, from June 2020 through December 2020.METHODSParticipants (n = 7935) were recruited through electronic advertising and received materials for a self-sampled dried-blood spot assay through the mail or a minimal contact in-person method. IgG against the receptor-binding domain of SARS-CoV-2 was measured using an established highly sensitive and highly specific assay.RESULTSOverall seroprevalence was 17.9%, with no significant difference between method of contact. Only 2.5% of participants reported having had a diagnosis of COVID-19 based on virus detection, consistent with a 7-fold greater exposure to SARS-CoV-2 measured by serology than that detected by viral testing. The range of IgG level observed in seropositive participants from this community survey overlapped with the range of IgG levels associated with COVID-19 cases having a documented positive PCR test. From a subset of those who participated in repeat testing, half of seropositive individuals retained detectable antibodies for 3 to 4 months.CONCLUSIONQuantitative IgG measurements with a highly specific and sensitive assay indicated more widespread exposure to SARS-CoV-2 than observed by viral testing. The range of IgG concentrations produced from these asymptomatic exposures was similar to IgG levels occurring after documented nonhospitalized COVID-19, which were considerably lower than those produced from hospitalized COVID-19 cases. The differing ranges of IgG response, coupled with the rate of decay of antibodies, may influence response to subsequent viral exposure and vaccine.FundingNational Science Foundation grant 2035114, NIH grant 3UL1TR001422-06S4, NIH National Center for Advancing Translational Sciences grants UL1 TR001422 and UL1 TR002389, Dixon Family Foundation, Northwestern University Cancer Center (NIH grant P30 CA060553), and Walder Foundation's Chicago Coronavirus Assessment Network.
SARS-CoV-2 的血清流行率估计值差异很大，可能会影响疫苗接种反应。我们在 2020 年 6 月至 2020 年 12 月期间，在美国一个大都市地点芝加哥，确定了 IgG 水平。
通过电子广告招募参与者（n = 7935），通过邮件或最低限度的接触方式为他们邮寄自我采样的干血斑检测材料。使用一种已建立的高度敏感和高度特异的检测方法测量针对 SARS-CoV-2 受体结合域的 IgG。
总体血清流行率为 17.9%，接触方式之间无显著差异。仅有 2.5%的参与者报告根据病毒检测确诊过 COVID-19，这与通过血清学检测到的 SARS-CoV-2 暴露量比通过病毒检测检测到的要高 7 倍一致。从社区调查中血清阳性参与者观察到的 IgG 水平范围与与记录阳性 PCR 检测的 COVID-19 病例相关的 IgG 水平范围重叠。从那些参加重复检测的亚组中，一半的血清阳性个体保留可检测的抗体长达 3 至 4 个月。
使用高度特异和敏感的检测方法进行定量 IgG 测量表明，SARS-CoV-2 的暴露范围比通过病毒检测观察到的更广泛。从这些无症状暴露中产生的 IgG 浓度范围与记录的非住院 COVID-19 后发生的 IgG 水平相似，远低于住院 COVID-19 病例产生的 IgG 水平。不同范围的 IgG 反应，加上抗体衰减率，可能会影响对随后的病毒暴露和疫苗的反应。
美国国家科学基金会格兰特 2035114、NIH 格兰特 3UL1TR001422-06S4、NIH 国家转化医学科学中心格兰特 UL1 TR001422 和 UL1 TR002389、Dixon 家庭基金会、西北大学癌症中心（NIH 格兰特 P30 CA060553）和 Walder 基金会的芝加哥冠状病毒评估网络。
