The Foundation for Medical Research, Mumbai, Maharashtra, India.
Molecular Laboratory, Viral Research, and Diagnostic Laboratory, Kasturba Hospital for Infectious Diseases, Sane Guruji Marg, Mumbai, Maharashtra, India.
PLoS One. 2021 Apr 12;16(4):e0249525. doi: 10.1371/journal.pone.0249525. eCollection 2021.
Infectious respiratory particles expelled by SARS-CoV-2 positive patients are attributed to be the key driver of COVID-19 transmission. Understanding how and by whom the virus is transmitted can help implement better disease control strategies. Here we have described the use of a noninvasive mask sampling method to detect and quantify SARS-CoV-2 RNA in respiratory particles expelled by COVID-19 patients and discussed its relationship to transmission risk. Respiratory particles of 31 symptomatic SARS-CoV-2 positive patients and 31 asymptomatic healthy volunteers were captured on N-95 masks layered with a gelatin membrane in a 30-minute process that involved talking/reading, coughing, and tidal breathing. SARS-CoV-2 viral RNA was detected and quantified using rRT-PCR in the mask and in concomitantly collected nasopharyngeal swab (NPS) samples. The data were analyzed with respect to patient demographics and clinical presentation. Thirteen of 31(41.9%) patients showed SARS-COV-2 positivity in both the mask and NPS samples, while 16 patients were mask negative but NPS positive. Two patients were both mask and NPS negative. All healthy volunteers except one were mask and NPS negative. The mask positive patients had significantly lower NPS Ct value (26) compared to mask negative patients (30.5) and were more likely to be rapid antigen test positive. The mask positive patients could be further grouped into low emitters (expelling <100 viral copies) and high emitters (expelling >1000 viral copies). The study presents evidence for variation in emission of SARS-CoV-2 virus particles by COVID-19 patients reflecting differences in infectivity and transmission risk among individuals. The results conform to reported secondary infection rates and transmission and also suggest that mask sampling could be explored as an effective tool to assess individual transmission risks, at different time points and during different activities.
SARS-CoV-2 阳性患者呼出的传染性呼吸道飞沫被认为是 COVID-19 传播的关键驱动因素。了解病毒是如何以及由谁传播的，可以帮助实施更好的疾病控制策略。在这里，我们描述了一种非侵入性的口罩采样方法，用于检测和量化 COVID-19 患者呼出的 SARS-CoV-2 RNA，并讨论了它与传播风险的关系。在 30 分钟的过程中，我们使用带有明胶膜的 N-95 口罩收集了 31 名有症状的 SARS-CoV-2 阳性患者和 31 名无症状健康志愿者呼出的呼吸道飞沫，涉及说话/阅读、咳嗽和潮式呼吸。使用 rRT-PCR 在口罩和同时采集的鼻咽拭子（NPS）样本中检测和定量 SARS-CoV-2 病毒 RNA。对患者的人口统计学和临床表现进行了数据分析。在 31 名患者中，有 13 名（41.9%）在口罩和 NPS 样本中均呈 SARS-COV-2 阳性，而 16 名患者口罩阴性但 NPS 阳性。两名患者口罩和 NPS 均为阴性。除一名外，所有健康志愿者的口罩和 NPS 均为阴性。与口罩阴性患者（30.5）相比，口罩阳性患者的 NPS Ct 值（26）明显较低，并且更有可能快速抗原检测阳性。口罩阳性患者可以进一步分为低排放者（排放<100 个病毒拷贝）和高排放者（排放>1000 个病毒拷贝）。该研究为 COVID-19 患者呼出的 SARS-CoV-2 病毒颗粒的排放变化提供了证据，反映了个体之间的感染性和传播风险的差异。研究结果与报告的二次感染率和传播相符，也表明口罩采样可以作为一种有效的工具，在不同时间点和不同活动期间评估个体的传播风险。
