Transmission of SARS-CoV-2 by inhalation of respiratory aerosol in the Skagit Valley Chorale superspreading event
Transmission of SARS-CoV-2 by inhalation of respiratory aerosol in the Skagit Valley Chorale superspreading event
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DOI：
10.1111/ina.12751
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发表时间：
2020-10-13
期刊：
影响因子：
5.8
通讯作者：
Noakes, Catherine
中科院分区：
文献类型：
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作者：
Miller, Shelly L.;Nazaroff, William W.;Noakes, Catherine
于2020年COVID-19疫情期间，一名有症状的指示病例于3月10日出席斯卡吉特山谷合唱团（SVC）的每周排练后爆发。彩排结束后，61名SVC成员中有53名被确认或强烈怀疑感染了COVID-19，其中两人死亡。通过气溶胶途径的传播是可能的;看来无论是污染物或弹道飞沫传播都不可能解释很大一部分病例。识别这类案件的特征，以更好地理解促进超级传播事件的因素，这一点至关重要。基于一个有条件的假设，在这次疫情的传播是由一个指标病例产生的呼吸道气溶胶吸入为主，我们使用现有的证据来推断气溶胶传染性量子的排放率。我们探讨了感染的风险如何随几个影响因素而变化：通风率，事件持续时间和表面沉积。结果表明，最佳估计排放速率为970 +/- 390量子/小时。通过将气溶胶损失率增加到5 h（-1）并将事件持续时间从2.5 h缩短到1 h，感染风险将降低2倍。
During the 2020 COVID-19 pandemic, an outbreak occurred following attendance of a symptomatic index case at a weekly rehearsal on 10 March of the Skagit Valley Chorale (SVC). After that rehearsal, 53 members of the SVC among 61 in attendance were confirmed or strongly suspected to have contracted COVID-19 and two died. Transmission by the aerosol route is likely; it appears unlikely that either fomite or ballistic droplet transmission could explain a substantial fraction of the cases. It is vital to identify features of cases such as this to better understand the factors that promote superspreading events. Based on a conditional assumption that transmission during this outbreak was dominated by inhalation of respiratory aerosol generated by one index case, we use the available evidence to infer the emission rate of aerosol infectious quanta. We explore how the risk of infection would vary with several influential factors: ventilation rate, duration of event, and deposition onto surfaces. The results indicate a best-estimate emission rate of 970 +/- 390 quanta/h. Infection risk would be reduced by a factor of two by increasing the aerosol loss rate to 5 h(-1)and shortening the event duration from 2.5 to 1 h.