In this population-based study, we identified 307 confirmed COVID-19 cases from massive surveillance, including 129,551 individuals screened at fever clinics or returning from Hubei and 3710 close contacts of confirmed COVID-19 patients. Among them, 17 patients were asymptomatic at initial clinical assessment. These asymptomatic patients on admission accounted for a small proportion of all patients (5.54%) with relatively weak transmissibility, and the detection rate was 0.35 per 100 close contacts. Moreover, the dynamics of symptoms of the 307 patients showed that the interval from symptom remission to the final negativity of viral nucleic acid was 5.0 days (IQR 2.0 to 11.0 days), with 14 patients (4.56%) having re-detectable viral RNA after discharge. Together, our findings suggested asymptomatic carriers and presymptomatic patients only accounted for a small proportion of COVID-19. Also, the asymptomatic phase in during recovery of COVID-19 urged that negativity in viral RNA is necessary as de-isolation criteria and follow-up is recommended.

中文翻译：

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2019 年冠状病毒病 (COVID-19) 的无症状患者和无症状阶段：一项基于人群的监测研究


在这项基于人群的研究中，我们通过大规模监测发现了 307 例确诊的 COVID-19 病例，其中包括 129,551 名在发热门诊筛查或从湖北返回的人以及 3710 名确诊的 COVID-19 患者的密切接触者。其中，17名患者在初步临床评估时没有症状。这些入院时无症状的患者占所有患者的比例较小（5.54%），传染性相对较弱，检出率为每100名密切接触者0.35例。此外，307例患者的症状动态显示，从症状缓解到病毒核酸最终转阴的时间间隔为5.0天（IQR 2.0至11.0天），其中14名患者（4.56%）在治疗后可重新检测到病毒RNA。释放。总之，我们的研究结果表明，无症状携带者和症状前患者仅占 COVID-19 的一小部分。此外，COVID-19 恢复期间的无症状阶段表明，病毒 RNA 呈阴性是必要的，因为建议解除隔离标准和随访。