Cadham Provincial Laboratory (Bullard, Dust, Hedley, Alexander, Van Caeseele), Manitoba Health; Department of Pediatrics & Child Health (Bullard, Strong, Lee, Van Caeseele, Poliquin), University of Manitoba; National Microbiology Laboratory (Funk, Garnett, Tran, Bello, Strong, Poliquin), Public Health Agency of Canada; Departments of Anesthesiology and Medicine (Funk), Section of Critical Care, University of Manitoba; Department of Medical Microbiology & Infectious Diseases (Garnett, Tran, Bello, Alexander), University of Manitoba; Communicable Disease Control, Public Health (Lee), Manitoba Health; Epidemiology and Surveillance Unit (Waruk, Loeppky), Manitoba Health; Department of Community Health Science (Loeppky), University of Manitoba. Winnipeg, Man.
CMAJ. 2021 Apr 26;193(17):E601-E606. doi: 10.1503/cmaj.210263. Epub 2021 Apr 9.
The role of children in the transmission and community spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is unclear. We aimed to quantify the infectivity of SARS-CoV-2 in nasopharyngeal samples from children compared with adults.
We obtained nasopharyngeal swabs from adult and pediatric cases of coronavirus disease 2019 (COVID-19) and from their contacts who tested positive for SARS-CoV-2 in Manitoba between March and December 2020. We compared viral growth in cell culture, cycle threshold values from the reverse transcription polymerase chain reaction (RT-PCR) of the SARS-CoV-2 envelope (E) gene and the 50% tissue culture infective dose (TCID/mL) between adults and children.
Among 305 samples positive for SARS-CoV-2 by RT-PCR, 97 samples were from children aged 10 years or younger, 78 were from children aged 11-17 years and 130 were from adults (≥ 18 yr). Viral growth in culture was present in 31% of samples, including 18 (19%) samples from children 10 years or younger, 18 (23%) from children aged 11-17 years and 57 (44%) from adults (children v. adults, odds ratio 0.45, 95% confidence interval [CI] 0.28-0.72). The cycle threshold was 25.1 (95% CI 17.7-31.3) in children 10 years or younger, 22.2 (95% CI 18.3-29.0) in children aged 11-17 years and 18.7 (95% CI 17.9-30.4) in adults ( < 0.001). The median TCID/mL was significantly lower in children aged 11-17 years (316, interquartile range [IQR] 178-2125) than adults (5620, IQR 1171 to 17 800, < 0.001). Cycle threshold was an accurate predictor of positive culture in both children and adults (area under the receiver-operator curve, 0.87, 95% CI 0.81-0.93 v. 0.89, 95% CI 0.83-0.96, = 0.6).
Compared with adults, children with nasopharyngeal swabs that tested positive for SARS-CoV-2 were less likely to grow virus in culture, and had higher cycle thresholds and lower viral concentrations, suggesting that children are not the main drivers of SARS-CoV-2 transmission.
儿童在严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）的传播和社区传播中的作用尚不清楚。我们旨在定量比较儿童与成人鼻咽样本中 SARS-CoV-2 的传染性。
我们从 2020 年 3 月至 12 月期间在马尼托巴省感染 2019 年冠状病毒病（COVID-19）的成人和儿科病例及其咽拭子阳性的接触者中获得了鼻咽拭子。我们比较了细胞培养中病毒的生长、SARS-CoV-2 包膜（E）基因逆转录聚合酶链反应（RT-PCR）的循环阈值以及儿童与成人之间的 50%组织培养感染剂量（TCID/mL）。
在通过 RT-PCR 检测为 SARS-CoV-2 阳性的 305 个样本中，有 97 个来自 10 岁或以下的儿童，78 个来自 11-17 岁的儿童，130 个来自成人（≥18 岁）。培养中存在病毒生长的有 31%的样本，其中 18 个（19%）来自 10 岁或以下的儿童，18 个（23%）来自 11-17 岁的儿童，57 个（44%）来自成人（儿童与成人相比，优势比 0.45，95%置信区间 [CI] 0.28-0.72）。儿童 10 岁或以下的循环阈值为 25.1（95%CI 17.7-31.3），儿童 11-17 岁的循环阈值为 22.2（95%CI 18.3-29.0），成人的循环阈值为 18.7（95%CI 17.9-30.4）（<0.001）。11-17 岁儿童的中位 TCID/mL 明显低于成人（11-17 岁儿童 316，四分位距 [IQR] 178-2125，成人 5620，IQR 1171-17800，<0.001）。循环阈值在儿童和成人中都是培养阳性的准确预测因子（受试者工作特征曲线下面积，0.87，95%CI 0.81-0.93 v. 0.89，95%CI 0.83-0.96，=0.6）。
与成人相比，咽拭子检测 SARS-CoV-2 阳性的儿童在培养中更不易生长病毒，其循环阈值更高，病毒浓度更低，这表明儿童不是 SARS-CoV-2 传播的主要驱动因素。
