Department of Respiratory Sciences, University of Leicester, Leicester, UK; Department of Infectious Diseases and HIV Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK; Li Ka Shing Center for Health Information and Discovery, Oxford Big Data Institute, University of Oxford, UK.
Department of Respiratory Sciences, University of Leicester, Leicester, UK; Department of Clinical Microbiology, University Hospitals of Leicester NHS Trust, Leicester, UK.
Clin Microbiol Infect. 2023 Feb;29(2):254.e1-254.e6. doi: 10.1016/j.cmi.2022.07.005. Epub 2022 Jul 14.
No studies have examined longitudinal patterns of naturally exhaled SARS-CoV-2 RNA viral load (VL) during acute infection. We report this using facemask sampling (FMS) and assessed the relationship between emitted RNA VL and household transmission.
Between December 2020 and February 2021, we recruited participants within 24 hours of a positive RT-qPCR on upper respiratory tract sampling (URTS) (day 0). Participants gave FMS (for 1 hour) and URTS (self-taken) on seven occasions up to day 21. Samples were analysed by RT-qPCR (from sampling matrix strips within the mask) and symptom diaries were recorded. Household transmission was assessed through reporting of positive URTS RT-qPCR in household contacts.
Analysis of 203 FMS and 190 URTS from 34 participants showed that RNA VL peaked within the first 5 days following sampling. Concomitant URTS, FMS RNA VL, and symptom scores, however, were poorly correlated, but a higher severity of reported symptoms was associated with FMS positivity up to day 5. Of 28 participants who had household contacts, 12 (43%) reported transmission. Frequency of household transmission was associated with the highest (peak) FMS RNA VL obtained (negative genome copies/strip: 0% household transmission; 1 to 1000 copies/strip: 20%; 1001 to 10 000 copies/strip: 57%; >10 000 copies/strip: 75%; p = 0.048; age adjusted OR of household transmission per log increase in copies/strip: 4.97; 95% CI, 1.20-20.55; p = 0.02) but not observed with peak URTS RNA VL.
Exhaled RNA VL measured by FMS is highest in early infection, can be positive in symptomatic patients with concomitantly negative URTS, and is strongly associated with household transmission.
目前尚无研究检测急性感染期间自然呼出的 SARS-CoV-2 RNA 病毒载量（VL）的纵向变化模式。我们使用口罩采样（FMS）报告了这一点，并评估了排放 RNA VL 与家庭传播之间的关系。
2020 年 12 月至 2021 年 2 月期间，我们在接受上呼吸道采样（URTS）的 RT-qPCR 阳性后 24 小时内招募参与者（第 0 天）。参与者在第 0 天至第 21 天期间进行了 7 次 FMS（1 小时）和 URTS（自我采集）。使用 RT-qPCR 分析样本（来自口罩内采样矩阵条）并记录症状日记。通过报告家庭接触者中 URTS RT-qPCR 的阳性结果来评估家庭传播。
对 34 名参与者的 203 个 FMS 和 190 个 URTS 进行分析显示，RNA VL 在采样后 5 天内达到峰值。然而，URTS、FMS RNA VL 和症状评分之间的相关性较差，但报告症状的严重程度与第 5 天之前的 FMS 阳性相关。在 28 名有家庭接触者的参与者中，有 12 名（43%）报告了传播。家庭传播的频率与获得的最高（峰值）FMS RNA VL 相关（阴性基因组拷贝/条：0%家庭传播；1 至 1000 拷贝/条：20%；1001 至 10000 拷贝/条：57%；>10000 拷贝/条：75%；p=0.048；每增加 1 拷贝/条的家庭传播的对数优势比：4.97；95%CI，1.20-20.55；p=0.02），但与 URTS RNA VL 的峰值无关。
通过 FMS 测量的呼出 RNA VL 在感染早期最高，在伴有同时性阴性 URTS 的症状患者中可为阳性，并且与家庭传播密切相关。
