key: cord-0836115-6bo49j5k
authors: Li, Jiajun; Wei, Xiaoyu; Tian, Wenguang; Zou, Jingbo; Wang, Yue; Xue, Wei; Xiao, Qing; Huang, Wenxiang
title: Clinical features of discharged COVID-19 patients with an extended SARS-CoV-2 RNA positive signal in respiratory samples
date: 2020-06-06
journal: Virus Res
DOI: 10.1016/j.virusres.2020.198047
sha: 23041e6664ec641eaa34a8f3efe394d6df391ae2
doc_id: 836115
cord_uid: 6bo49j5k

• Patients may remain positive for SARS-CoV-2 RNA in respiratory samples for some time after hospital discharge; • Although this signal may represent non-infectious virus, it seems safe to quarantine recovered patients for at least two weeks; • Stricter criteria for hospital discharge may be warranted.

glucocorticoid therapy. The median durations of hospital stay and course of disease were 17.0 days (IQR, ) and 20.0 days (IQR, 16.0-24.5), respectively. Notably, there were no significant differences between patients with positive SARS-CoV-2 RNA results and patients with persistently negative SARS-CoV-2 RNA results in age, gender, hospital stay, course of disease, disease severity, or glucocorticoid therapy (all P > 0.05) ( Table 2) .

Furthermore, in Group A, 16 patients (36.36% of the 44 patients) were positive for SARS-CoV-2 RNA on throat swabs after discharge. One of the 16 patients presented with a mild cough, one had occasional chest tightness, and neither had fever or progressed to pneumonia. The mean durations from patient discharge to first testing positive for SARS-CoV-2 RNA, from first testing positive to testing negative for SARS-CoV-2 RNA after discharge, and from discharge to negative for SARS-CoV-2 RNA again were 3.9 days (range, 1-17), 5.4 days (range, 2-16) and 8.4 days (range, 2-18), respectively. In Group B, 3 patients (11.11% of the 27 patients) were positive for SARS-CoV-2 RNA, and all were asymptomatic. The mean durations from patient discharge to first testing positive for SARS-CoV-2 RNA, from first testing positive to testing negative for SARS-CoV-2 RNA after discharge, and from discharge to testing negative for SARS-CoV-2 RNA again were 6.7 days (range, 3-10), 3.0 days (range, 2-4) and 8.3 days (range, 4-12), respectively. Notably, compared with that of patients in Group A, a lower proportion of patients in Group B tested positive for SARS-CoV-2 RNA after discharge (P = 0.02) (Table 1) , and Group B required longer hospital stays (Group A vs. Group B; median days, 14.5 (IQR, 10.0-17.0) vs 25.0 (14.5-27.0); P < 0.0001) ( Table 2) . Moreover, antibody detection showed that 8 of 16 patients in Group A were positive for IgM and IgG, and none of the 3 patients in Group B were both IgM and IgG positive ( Table 1) , suggesting that the patients in Group B may have already been in the middle or late stages of infection, while some patients in Group A may have still been in the active phase of infection.

Based on the above, we would like to recommend the following: (1)

Patients may remain positive for SARS-CoV-2 RNA in respiratory samples for some time after hospital discharge; (2) stricter criteria for hospital discharge may be warranted; (3) the patients who remained positive for SARS-CoV-2 RNA were nearly asymptomatic and had a low viral load that did not represent reactivation of SARS-CoV-2. However, due to the urgency of the epidemic, we did not conduct viral culture to find direct evidence that this phenomenon will cause infection, but their potential infectiousness needs further attention. Therefore, it seems safe to quarantine recovered patients for at least two weeks to reduce their transmission potential, as they may excrete the virus intermittently (Pan et al., 2020; Zou et al., 2020) . The study was approved by the Ethics Committee of the First Affiliated Hospital of Chongqing Medical University and the Yongchuan Hospital of Chongqing Medical University. And, no informed consent is required.

We declare no competing interests. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

CRediT authorship contribution statement Abbreviations: IQR, interquartile range; COVID-19, coronavirus disease 2019; a indicate patients with SARS-VoC-2 RNA turned to positive, and b indicate patients with SARS-VoC-2 RNA remained negative; c P1 values indicate differences between the patients with positive SARS-VoC-2 RNA and patients with consistently negative SARS-VoC-2 RNA; d P2 values indicate differences between the Group A and Group B. P < 0.05 was considered statistically significant.

Positive RT-PCR Test Results in Patients Recovered From COVID-19

Diagnosis and treatment of 2019-nCoV pneumonia in China

Viral load of SARS-CoV-2 in clinical samples. The Lancet Infectious Diseases

SARS-CoV-2 Viral Load in Upper Respiratory Specimens of Infected Patients