key: cord-0809020-r0jxru85
authors: Syue, Ling-Shan; Hung, Yuan-Pin; Li i, Chia-Wen; Tsa, Chin-Shiang; Chen, Po-Lin; Li, Ming-Chi; Lee, Nan-Yao; Ko, Wen-Chien
title: De-isolation criterion of real-time PCR test in patients with COVID-19: two or three consecutive negative nasal swabs?
date: 2020-08-19
journal: J Microbiol Immunol Infect
DOI: 10.1016/j.jmii.2020.08.014
sha: 8124aeef3a9947814a51c71cdfe92a80e928f347
doc_id: 809020
cord_uid: r0jxru85

nan

banning international or domestic travel, confirmed case isolation and quarantine policy to 25 contain this outbreak but also impact global economic and caused huge healthcare system 26 burden. Since the studies of virological infectivity and dynamic transmissibility are ongoing, 27 different policies had been applied in different countries. The interim guidance from Centers 28 for Disease Control and Prevention (CDC), USA suggested that the test-based strategy, i.e., 29 two consecutive negative results of oropharyngeal swabs by real-time-polymerase chain 30 reaction (RT-PCR), could be the criterion for return to work or de-isolation. However, Taiwan 31 CDC recommended three consecutive negative results as the de-isolation criterion for 32 confirmed cases before Jun. 17, 2020. So far, the contagious period of symptomatic or 33 asymptomatic cases of COVID-19 is not fully understood, and adoption of the stricter policy, 34 three consecutive negative results, may avoid person-to-person transmission. However, 35 prolonged shedding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA 36 in nasopharyngeal swabs or lower respiratory tract aspirates in the cases of COVID-19 after 37 clinical resolution and seroconversion had been reported [1] and prolonged isolation or 38 hospitalization and the consumption of personal protective equipment were two major 39 disadvantages of applying strict policy. This observation study is aimed to report the effect of 40 different de-isolation criterion. 41

From Feb. 1 to Apr. 21, 2020, 12 patients of COVID-19 admitted to two hospitals at 42 southern Taiwan were included for analysis. Their median age was 23.5 years with a range of 43 16-52 years, and 6 (50%) were males. Only one had underlying hypertension with regular 44 medical control. Nine patients had fever and cough, but no patient experienced severe anosmia and two of them only had anosmia without rhinorrhea or other discomfort. All 47 patients except a naval crew were diagnosed within one week after symptom onset and their 48 median interval between the symptom onset and diagnosis was 2 days, with a range of 1-6 49 days. Chest X-ray films showed pulmonary infiltrations or opacities in five patients, and four 50 required supplemental oxygen during the initial week of hospitalization. Except four patients 51 had prolonged anosmia during hospitalization, the median interval between diagnosis and 52 symptom resolution in other eight patients was 3.5 days (range 0-7 days). Their symptoms 53 improved before negative swab tests. Ten patients ever received oral hydroxycholoquine 54 therapy. Oropharyngeal/nasopharyngeal swab specimens were collected every 2-4 days and 55

were tested for viral RNA in one hospital, according to the laboratory method recommended 

Prolonged virus 97 shedding even after seroconversion in a patient with COVID-19

Detection of 2019-nCoV viral nucleic acid. 2020. 100 version 2.2

Evidence base of 103 incubation periods, periods of infectiousness and exclusion policies for the control of 104 communicable diseases in schools and preschools

Virological assessment of hospitalized patients With COVID-2019

Predicting 110 infectious SARS-CoV-2 from diagnostic samples

Findings from investigation and analysis of re-positive cases

patients with COVID-19. The alphabetic is the case No. and numerical values are the illness 117 days of oropharyngeal swab sampling after the day of confirmed diagnosis of COVID-19 (D0). 118Black boxes indicate positive PCR results, and the boxes with dots negative results. The dotted 119 circles show the gap intervals between two de-isolation criterion of two and three consecutive 120 negative real-time polymerase-chain reaction results of oropharyngeal swabs. 121