Can the cycle threshold (Ct) value of RT-PCR test for SARS CoV2 predict infectivity among close contacts?
Can the cycle threshold (Ct) value of RT-PCR test for SARS CoV2 predict infectivity among close contacts?
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DOI：
10.1016/j.jiph.2021.08.013
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发表时间：
2021-09
影响因子：
6.7
通讯作者：
Al-Thani MHJ
中科院分区：
文献类型：
--
作者：
Al Bayat S;Mundodan J;Hasnain S;Sallam M;Khogali H;Ali D;Alateeg S;Osama M;Elberdiny A;Al-Romaihi H;Al-Thani MHJ
新冠肺炎全球大流行是一场史无前例的突发卫生事件。对感染者的快速识别和隔离至关重要。卡塔尔国家卫生战略指挥组通过了一例阳性病例RT-PCR结果的CT值下限30，以决定其密切接触者的隔离时间和隔离期。检测CT值是否以30为界值反映密切接触者的传染性潜在性。2020年7月报告的所有阳性病例，其接触者已被追踪和拭子，在删除个人识别符后从数据库中提取。密切接触是指任何人在距离确诊阳性病例2米的范围内15分钟或更长时间，没有任何个人防护装备。进行描述性分析，并对ct<；30和>；30接触者阳性率差异的显著性进行检验。对2,308例新冠肺炎阳性患者进行了随访。超过四分之三的人的CT值为<；30，平均CT值为24.05(+6.48)。平均每个病例要擦拭6个接触者。超过一半的阳性病例至少有一个继发病例，中位数阳性率为12.5%。Ct值临界值30与二次传播之间存在显著关系(在Ct值为30的患者中，风险是后者的1.5倍)。Ct值<30或<lt；30的阳性病例密切接触者的中位数阳性率有显著差异。还需要结合聚合酶链式反应分析、培养研究和接触者追踪的进一步研究，以确定哪些因素可以可靠地预测新冠肺炎患者的感染状态。
COVID-19 global pandemic is an unprecedented health emergency. Rapid identification and isolation of infected individuals is crucial. Qatar’s National Health Strategic Command Group adopted a cut off 30 for Ct value of RT-PCR result of a positive case to decide on duration of isolation and quarantine period for their close contacts. To test if Ct value cut off 30 reflects on the infectivity potential among close contacts. All positive cases reported during July’ 2020 whose contacts had been traced and swabbed were extracted from database after removing personal identifiers. Close-contact was defined as anybody who has been within 2 m distance of a confirmed positive case for 15 min or more, without any personal protection equipment. Descriptive analysis was done and test of significance of difference in positivity among the contacts of those with ct < 30 and >30 was done. 2308 COVID-19 positive cases were followed up. More than three-quarters had a Ct value < 30, with a mean Ct value of 24.05(+6.48). On an average 6 contacts were swabbed per case. More than half the positive cases followed up had at least one secondary case, with median positivity rate 12.5%. A significant relation was noted between Ct value cut-off 30 and secondary transmission (1.5 times more risk among those with Ct value < 30). A significant difference was noted in median positivity rate between close contacts of positive cases with Ct value > 30 or <30. Further studies combining PCR assays, culture studies and contact tracing are needed to define which factors can be used to reliably predict the infectious status of patients with COVID-19.
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DOI：
10.15585/mmwr.mm6911e1
发表时间：
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期刊：
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影响因子：
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作者：
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发表时间：
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作者：
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