key: cord-0969973-r2a2ozrc
authors: Yan, Xiquan; Han, Xiaotong; Fan, Yong; Fang, Zhixiong; Long, Da; Zhu, Yimin
title: Duration of SARS-CoV-2 viral RNA in asymptomatic carriers
date: 2020-05-24
journal: Crit Care
DOI: 10.1186/s13054-020-02952-0
sha: f77f8c7ec13314babd158d09de5ceccd9264ce25
doc_id: 969973
cord_uid: r2a2ozrc

nan

course of the 24 patients with respiratory samples that were positive for SARS-CoV-2 RNA is shown in Fig. 1 . Notably, patient 2 carried SARS-CoV-2 viral for 32 days continuously after exposure to COVID-19 and tested positive for viral RNA in the respiratory sample for 13 days after first positive test onset.

The results indicate that asymptomatic human can carry SARS-CoV-2 viral RNA after exposure to COVID-19, and the carriage seems long-lived. Yet, the viability of SARS-CoV-2 detected on qRT-PCR in carriers remains to be proved by means of viral culture. Due to limited resources, we did not perform these tests. Further study is needed to determine the potential for and mode of contagion of asymptomatic carriers to develop more scientific control strategies.

The long duration of asymptomatic infection with SARS-CoV-2 may warrant a reassessment of quarantine as the current outbreak. And it is of great public health significance to strictly monitor close contacts via multiple nucleic acid screenings to contain potential outbreaks.

Zhang and colleagues provided evidence of asymptomatic transmission [2] , and the relatively high proportion of asymptomatic infections could have public health implications [3] . To prevent and control this highly infectious disease in early phases, people with close contact with SARS-CoV-2 infection should be closely monitored and examined to rule out infection, even if they do not have any symptoms. The US Centers for Disease Control and Prevention recommends that contacts of asymptomatic carriers self-isolate for 14 days [4] . Social distancing is one of the most important ways to cut off transmission routes-people cannot pass on infection if they do not come into contact with other people. Quarantine of asymptomatic carriers and identification of contacts are a crucial part of these control efforts.

This study is limited by the small sample size. Largescale multicenter studies are needed to verify our findings. There is a great need for further studies on the mechanism by which asymptomatic carriers could acquire and carry SARS-CoV-2 that causes COVID-19. These results highlighted the importance of quarantine. Hence, with extensive efforts on close contact tracing and longitudinally surveillance via SARS-CoV-2 viral RNA tests, the prevention of SARS-CoV-2 infection would prove challenging.

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A novel coronavirus from patients with pneumonia in China

Familial cluster of COVID-19 infection from an asymptomatic

Covert coronavirus infections could be seeding new outbreaks

Public Health recommendations for community-related exposure

We thank all patients involved in the study.

All authors were the major contributors in writing the manuscript and approved the final manuscript.

The authors declare that they have no competing interests.