key: cord-1039048-76bbmnbw
authors: Kadnur, Harshit B; Ray, Animesh
title: Letter to the editor regarding the article ‘Prolonged persistence of SARS-CoV-2 in the upper respiratory tract of asymptomatic infected individuals’
date: 2020-09-18
journal: QJM
DOI: 10.1093/qjmed/hcaa268
sha: 08fa1163304b1593071afcd56fa4eee03cb84cb0
doc_id: 1039048
cord_uid: 76bbmnbw

nan

Sir, Apropos of the article by Saurabh et al, 1 we would like to mention a few pertinent points.

First, there has been a paradigm shift in the discharge policy of COVID-19 patients, including asymptomatic ones, from test-based strategy to symptom-based strategy. For asymptomatic patients, who are not immunocompromised, transmission-based precautions may be discontinued 10 days after the first positive COVID-19 test. 2 This is largely based on studies, 3, 4 which show that the viability of isolated viruses become negligible after the said duration. In fact, viral RNA may be detected months after initial infection though with negligible infectiousness after the initial 8 days, suggesting RT PCR as a poor markers of infectiousness. For those who are severely ill or immunocompromised, the duration can be increased up to 20 days as infectiousness is prolonged. 5 In test-based strategy for asymptomatic patients, two respiratory specimens (≥ 24 hours apart) are required to be negative, irrespective of initial date of COVID-19 detection. In light of these evidences, the conclusion of the authors to increase the period of home isolation to three weeks is contradictory.

Secondly, the authors have quoted Bullard et al, 6 to support the importance of their finding in this study, saying that low cyclic threshold (Ct) (not measured in present study) implies high infectivity. The quoted study showed that STT (symptom onset to test >/= 8 days) and

Ct >24 was suggestive of lower infectiousness; is however is not relevant to the present study since it did not specifically concern asymptomatic patients.

Prolonged persistence of SARS-CoV-2 in the upper respiratory tract of asymptomatic infected individuals

Centers for Disease Control and Prevention

Virological assessment of hospitalized patients with COVID-2019

Associations of clinical characteristics and treatment regimens with the duration of viral RNA shedding in patients with COVID-19

Shedding of infectious virus in hospitalized patients with coronavirus disease-2019 (COVID-19): duration and key determinants. medRxiv

Predicting infectious SARS-CoV-2 from diagnostic samples