Objectives

Studies comparing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA load in the upper respiratory tract (URT) between children and adults—who either presented with coronavirus disease 2019 (COVID-19) or were asymptomatic—have yielded inconsistent results. Here, we conducted a retrospective, single-centre study to address this issue.

Patients and methods

Included were 1184 consecutive subjects (256 children and 928 adults) testing positive for SARS-CoV-2 RNA in nasopharyngeal exudates (NPs); of these, 424 (121 children and 303 adults) had COVID-19 and 760 (135 children and 625 adults) were asymptomatic close contacts of COVID-19 patients. SARS-CoV-2 RNA testing was carried out using the TaqPath COVID-19 Combo Kit (Thermo Fisher Scientific, MS, USA). The AMPLIRUN® TOTAL SARS-CoV-2 RNA Control (Vircell SA, Granada, Spain) was used for estimating SARS-CoV-2 RNA loads (in copies/mL). SARS-CoV-2 RNA loads at the time of laboratory diagnosis (single specimen/patient) were used for comparison purposes.

Results

Median initial SARS-CoV-2 RNA load was lower (p 0.094) in children (6.98 log₁₀ copies/mL, range 3.0–11.7) than in adults (7.14 log₁₀ copies/mL, range 2.2–13.4) with COVID-19. As for asymptomatic individuals, median SARS-CoV-2 RNA load was comparable (p 0.97) in children (6.20 log₁₀ copies/mL, range 1.8–11.6) and adults (6.48 log₁₀ copies/mL, range 1.9–11.8). Children with COVID-19 symptoms displayed SARS-CoV-2 RNA loads (6.98 log₁₀ copies/mL, range 3.0–11.7) comparable to those of their asymptomatic counterparts (6.20 log₁₀ copies/mL, range 1.8–11.6) (p 0.61). Meanwhile in adults, median SARS-CoV-2 RNA load was significantly higher in symptomatic (7.14 log₁₀ copies/mL, range 2.2–13.4) than in asymptomatic subjects (6.48 log₁₀ copies/mL, range 1.9–11.8) (p < 0.001). Overall, the observed URT SARS-CoV-2 RNA clearance rate was faster in children than in adults.

Conclusions

Based on viral load data at the time of diagnosis, our results suggest that SARS-CoV-2-infected children, with or without COVID-19, may display NP viral loads of comparable magnitude to those found in their adult counterparts. However, children may have shorter viral shedding than adults.

中文翻译：

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有症状和无症状儿童和成人的上呼吸道 SARS-CoV-2 RNA 载量

目标

比较严重急性呼吸系统综合症冠状病毒 2 (SARS-CoV-2) 在儿童和成人之间上呼吸道 (URT) 中的 RNA 载量的研究——他们要么患有 2019 年冠状病毒病 (COVID-19) 要么没有症状——产生了不一致的结果. 在这里，我们进行了一项回顾性的单中心研究来解决这个问题。

患者和方法

其中包括 1184 名连续受试者（256 名儿童和 928 名成人）在鼻咽分泌物（NPs）中检测出 SARS-CoV-2 RNA 呈阳性；其中，424 人（121 名儿童和 303 名成人）患有 COVID-19，760 人（135 名儿童和 625 名成人）是 COVID-19 患者的无症状密切接触者。使用 TaqPath COVID-19 Combo Kit（Thermo Fisher Scientific，MS，USA）进行 SARS-CoV-2 RNA 检测。AMPLIRUN® TOTAL SARS-CoV-2 RNA Control（Vircell SA，Granada，西班牙）用于估计 SARS-CoV-2 RNA 载量（以拷贝/毫升为单位）。实验室诊断时的 SARS-CoV-2 RNA 载量（单个样本/患者）用于比较目的。

结果

儿童（6.98 log ₁₀拷贝/mL，范围 3.0-11.7）的SARS-CoV-2 RNA 初始载量中位数低于成人（7.14 log ₁₀拷贝/mL，范围 2.2-13.4）COVID-19 . 对于无症状个体，儿童（6.20 log ₁₀拷贝/mL，范围 1.8-11.6）和成人（6.48 log ₁₀拷贝/mL，范围 1.9-11.8）的SARS-CoV-2 RNA 载量中位数相当（p = 0.97 ）。有 COVID-19 症状的儿童表现出的 SARS-CoV-2 RNA 负荷（6.98 log ₁₀拷贝/mL，范围 3.0-11.7）与无症状儿童的 RNA 负荷（6.20 log ₁₀拷贝/mL，范围 1.8-11.6）相当（p 0.61 ）。同时，在成人中，有症状的 SARS-CoV-2 RNA 载量中位数显着更高（7.14 log ₁₀拷贝/毫升，范围 2.2–13.4）比无症状受试者（6.48 log ₁₀拷贝/毫升，范围 1.9–11.8）（p < 0.001）。总体而言，观察到的 URT SARS-CoV-2 RNA 清除率在儿童中比成人快。

结论

根据诊断时的病毒载量数据，我们的结果表明，感染 SARS-CoV-2 的儿童，无论是否有 COVID-19，其 NP 病毒载量可能与成年儿童的病毒载量相当。然而，儿童的病毒脱落时间可能比成人短。