Background/purpose

Superspreading events (SSEs) are pivotal in the spread of SARS-CoV-2. This study aimed to investigate an SSE of COVID-19 in a hospital and explore the transmission dynamics and heterogeneity of SSE.

Methods

We performed contact tracing for all close contacts in a cluster. We did nasopharyngeal or throat swabbing for SARS-CoV-2 by real-time RT-PCR. Environmental survey was performed. The epidemiological and clinical characteristics of the SSE were studied.

Results

Patient 1 with congestive heart failure and cellulitis, who had onset of COVID-19 two weeks after hospitalization, was the index case. Patient 1 led to 8 confirmed cases, including four health care workers (HCW). Persons tested positive for SARS-CoV-2 were HCW (n = 4), patient 1's family (n = 2), an accompanying person of an un-infected in-patient (n = 1), and an in-patient admitted before the SSE (n = 1). The attack rate among the HCW was 3.2 % (4/127). Environmental survey confirmed contamination at the bed rails, mattresses, and sink in the room patient 1 stayed, suggesting fomite transmission. The index case's sputum remained positive on illness day 35. Except one asymptomatic patient, at least three patients acquired the infection from the index case at the pre-symptomatic period. The effective reproduction number (R_t) was 0.9 (8/9).

Conclusion

The host factor (heart failure, longer viral shedding), transmissibility of SARS-CoV-2 (R_t, pre-symptomatic transmission), and possible multiple modes of transmission altogether contributed to the SSE. Rapid response and advance deployment of multi-level protection in hospitals could mitigate COVID-19 transmission to one generation, thereby reducing its impact on the healthcare system.

中文翻译：

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与 SARS-CoV-2 超级传播事件相关的 COVID-19 医院集群

背景/目的

超级传播事件 (SSE) 是 SARS-CoV-2 传播的关键。本研究旨在调查医院中 COVID-19 的 SSE，并探索 SSE 的传播动态和异质性。

方法

我们对集群中的所有密切接触者进行了接触者追踪。我们通过实时 RT-PCR 对 SARS-CoV-2 进行了鼻咽或咽喉拭子检测。进行了环境调查。研究了 SSE 的流行病学和临床特征。

结果

住院两周后出现 COVID-19 的患有充血性心力衰竭和蜂窝织炎的患者 1 是指示病例。患者 1 导致 8 例确诊病例，其中包括 4 名医护人员 (HCW)。SARS-CoV-2 检测呈阳性的人是 HCW（n = 4）、患者 1 的家人（n = 2）、未感染住院患者的陪同人员（n = 1）和之前入院的住院患者SSE (n = 1)。医护人员中的发病率为 3.2 % (4/127)。环境调查证实，患者 1 入住的房间的床栏、床垫和水槽受到污染，表明有污染物传播。指示病例的痰液在发病第35天仍为阳性。除1名无症状患者外，至少有3名患者在出现症状前由指示病例感染。_t ) 为 0.9 (8/9)。

结论

宿主因素（心力衰竭、较长的病毒脱落）、SARS-CoV-2 的传播性（R _t，症状前传播）以及可能的多种传播方式共同促成了 SSE。在医院中快速响应和提前部署多级保护可以将 COVID-19 传播到一代人，从而减少其对医疗保健系统的影响。