Division of Infectious Diseases, Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, Illinois, USA.
Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.
J Clin Microbiol. 2020 Dec 17;59(1). doi: 10.1128/JCM.02593-20.
The distribution of upper respiratory viral loads (VL) in asymptomatic children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unknown. We assessed PCR cycle threshold (Ct) values and estimated VL in infected asymptomatic children diagnosed in nine pediatric hospital testing programs. Records for asymptomatic and symptomatic patients with positive clinical SARS-CoV-2 tests were reviewed. Ct values were (i) adjusted by centering each value around the institutional median Ct value from symptomatic children tested with that assay and (ii) converted to estimated VL (numbers of copies per milliliter) using internal or manufacturer data. Adjusted Ct values and estimated VL for asymptomatic versus symptomatic children (118 asymptomatic versus 197 symptomatic children aged 0 to 4 years, 79 asymptomatic versus 97 symptomatic children aged 5 to 9 years, 69 asymptomatic versus 75 symptomatic children aged 10 to 13 years, 73 asymptomatic versus 109 symptomatic children aged 14 to 17 years) were compared. The median adjusted Ct value for asymptomatic children was 10.3 cycles higher than for symptomatic children ( < 0.0001), and VL were 3 to 4 logs lower than for symptomatic children ( < 0.0001); differences were consistent ( < 0.0001) across all four age brackets. These differences were consistent across all institutions and by sex, ethnicity, and race. Asymptomatic children with diabetes (odds ratio [OR], 6.5; = 0.01), a recent contact (OR, 2.3; = 0.02), and testing for surveillance (OR, 2.7; = 0.005) had higher estimated risks of having a Ct value in the lowest quartile than children without, while an immunocompromised status had no effect. Children with asymptomatic SARS-CoV-2 infection had lower levels of virus in their nasopharynx/oropharynx than symptomatic children, but the timing of infection relative to diagnosis likely impacted levels in asymptomatic children. Caution is recommended when choosing diagnostic tests for screening of asymptomatic children.
无症状感染严重急性呼吸综合征冠状病毒 2 （SARS-CoV-2）的儿童上呼吸道病毒载量（VL）的分布情况尚不清楚。我们评估了在 9 个儿科医院检测项目中诊断为感染无症状的儿童的 PCR 循环阈值（Ct）值并估算了 VL。回顾了无症状和有症状的临床 SARS-CoV-2 检测阳性患者的记录。对 Ct 值进行了以下处理：（i）将每个值围绕该检测中感染 SARS-CoV-2 的有症状儿童的机构中位 Ct 值进行中心化，（ii）使用内部或制造商数据将 Ct 值转换为估计的 VL（每毫升的拷贝数）。比较了无症状和有症状儿童的调整后 Ct 值和估计 VL（0 至 4 岁儿童 118 名无症状 vs. 197 名有症状，5 至 9 岁儿童 79 名无症状 vs. 97 名有症状，10 至 13 岁儿童 69 名无症状 vs. 75 名有症状，14 至 17 岁儿童 73 名无症状 vs. 109 名有症状）。无症状儿童的中位调整后 Ct 值比有症状儿童高 10.3 个循环（<0.0001），VL 比有症状儿童低 3 到 4 个对数级（ < 0.0001）；所有四个年龄组的差异均一致（ < 0.0001）。这些差异在所有机构中、在不同性别、种族和民族中均一致。与无症状儿童相比，患有糖尿病（比值比 [OR]，6.5； = 0.01）、近期接触史（OR，2.3； = 0.02）或进行监测检测（OR，2.7； = 0.005）的儿童有更高的 Ct 值处于最低四分位数的风险，而免疫功能低下的状态没有影响。与有症状儿童相比，无症状 SARS-CoV-2 感染儿童的鼻咽/口咽中的病毒水平较低，但感染与诊断的时间关系可能影响无症状儿童的病毒水平。在选择用于无症状儿童筛查的诊断检测时应谨慎。
