Background

An ongoing outbreak of coronavirus disease 2019 (COVID-19) has spread around the world. It is debatable whether asymptomatic COVID-19 virus carriers are contagious. We report here a case of the asymptomatic patient and present clinical characteristics of 455 contacts, which aims to study the infectivity of asymptomatic carriers.

Material and methods

455 contacts who were exposed to the asymptomatic COVID-19 virus carrier became the subjects of our research. They were divided into three groups: 35 patients, 196 family members and 224 hospital staffs. We extracted their epidemiological information, clinical records, auxiliary examination results and therapeutic schedules.

Results

The median contact time for patients was four days and that for family members was five days. Cardiovascular disease accounted for 25% among original diseases of patients. Apart from hospital staffs, both patients and family members were isolated medically. During the quarantine, seven patients plus one family member appeared new respiratory symptoms, where fever was the most common one. The blood counts in most contacts were within a normal range. All CT images showed no sign of COVID-19 infection. No severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections was detected in 455 contacts by nucleic acid test.

Conclusion

In summary, all the 455 contacts were excluded from SARS-CoV-2 infection and we conclude that the infectivity of some asymptomatic SARS-CoV-2 carriers might be weak.

中文翻译：

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一项关于无症状 SARS-CoV-2 携带者传染性的研究。

背景

持续爆发的 2019 年冠状病毒病 (COVID-19) 已在全球蔓延。无症状的 COVID-19 病毒携带者是否具有传染性尚有争议。我们在此报告一例无症状患者并呈现 455 名接触者的临床特征，旨在研究无症状携带者的传染性。

材料与方法

455 名接触过无症状 COVID-19 病毒携带者的接触者成为我们研究的对象。他们分为三组：35名患者、196名家属和224名医院工作人员。我们提取了他们的流行病学信息、临床记录、辅助检查结果和治疗方案。

结果

患者的中位接触时间为四天，家庭成员的中位接触时间为五天。心血管疾病占患者原有疾病的25%。除医院工作人员外，患者和家属均被医学隔离。在隔离期间，7名患者和1名家庭成员出现了新的呼吸道症状，其中发烧是最常见的。大多数接触者的血细胞计数都在正常范围内。所有 CT 图像均未显示 COVID-19 感染迹象。455名接触者核酸检测未发现严重急性呼吸综合征冠状病毒2型（SARS-CoV-2）感染。

结论

总之，所有 455 名接触者都被排除在 SARS-CoV-2 感染之外，我们得出结论，一些无症状 SARS-CoV-2 携带者的传染性可能较弱。