key: cord-329052-jan20ljs
authors: Gombar, Saurabh; Chang, Marcello; Hogan, Catherine A.; Zehnder, James; Boyd, Scott; Pinsky, Benjamin A.; Shah, Nigam H.
title: Persistent detection of SARS-CoV-2 RNA in patients and healthcare workers with COVID-19
date: 2020-05-30
journal: J Clin Virol
DOI: 10.1016/j.jcv.2020.104477
sha: 
doc_id: 329052
cord_uid: jan20ljs

BACKGROUND: Current guidelines for returning health care workers (HCW) to service after a positive SARS-CoV-2 RT-PCR test and ceasing of transmission precautions for patients is based on two general strategies. A test-based strategy that requires negative respiratory RT-PCR tests obtained after the resolution of symptoms. Alternatively, due to the limited availability of testing, many sites employ a symptom-based strategy that recommends excluding HCW from the workforce and keeping patients on contact precautions until a fixed period of time has elapsed from symptom recovery. The underlying assumption of the symptom-based strategy is that waiting for a fixed period of time is a surrogate for negative RT-PCR testing, which itself is a surrogate for the absence of shedding infectious virus. OBJECTIVES: To better understand the appropriate length of symptom based return to work and contact precaution strategies. STUDY DESIGN: We performed an observational analysis of 150 patients and HCW that transitioned from RT-PCR SARS-CoV-2 positive to negative over the course of 2 months at a US academic medical center. RESULTS: We found that the average time to transition from RT-PCR positive to negative was 24 days after symptom onset and 10 % remained positive even 33 days after symptom onset. No difference was seen in HCW and patients. CONCLUSIONS: These findings suggest until definitive evidence of the length of infective viral shedding is obtained that the fixed length of time before returning to work or ceasing contract precautions be revised to over one-month.

that waiting for a fixed period of time is a surrogate for negative RT-PCR testing, which itself is a surrogate for the absence of shedding infectious virus.

Objectives: To better understand the appropriate length of symptom based return to work and contact precaution strategies.

We performed an observational analysis of 150 patients and HCW that transitioned from RT-PCR SARS-CoV-2 positive to negative over the course of 2 months at a US academic medical center.

We found that the average time to transition from RT-PCR positive to negative was 24 days after symptom onset and 10% remained positive even 33 days after symptom onset. No difference was seen in HCW and patients.

These findings suggest until definitive evidence of the length of infective viral shedding is obtained that the fixed length of time before returning to work or ceasing contract precautions be revised to over one-month.

Health care workers (HCW) who test positive for SARS-CoV-2 via reverse transcriptase PCR (RT-PCR) of nasopharyngeal swab (NP) specimens are asked to self-quarantine and only return to work after symptoms resolve and/or a fixed duration of time has passed. Similarly, hospitalized patients with COVID-19 are subject to transmission-based precautions to limit nosocomial spread. The CDC provides guidance for HCW to return to work, and for J o u r n a l P r e -p r o o f discontinuation of transmission-based precautions in hospitalized patients, for confirmed or suspected COVID-19 infection 1 . Both of these guidelines, last updated on April 30th, offer two strategies to proceed with routine processes. A test-based strategy requires two consecutive negative respiratory RT-PCR tests obtained after the resolution of symptoms. Alternatively, due to the limited availability of testing, a symptom-based strategy recommends excluding HCW from the workforce and keeping patients on contact precautions until at least 3 days after symptomatic recovery, and at least 7 days since initial symptom onset.

The underlying assumption of the symptom-based strategy is that waiting for a certain period of time is a surrogate for negative RT-PCR testing, which itself is a surrogate for the absence of Table 1) .

For the patients, the average age was 57.2 years (standard deviation 21.7), with 48.7% female. Our study, and similarly all studies based on RT-PCR analysis do not directly measure infectivity. Our analysis could be overestimating the length of infectious spreading by detecting non-infectious viral shedding. Large trials that rely on methods that detect the infective virus (ie viral culture) have not yet been reported in the literature. Until such studies are completed we suggest that return to work and contact precaution guidelines should require negative PCR tests or assume viral shedding for 33 days following symptom onset.

Declarations of interest: none'. Tables: Table 1 : Selected demographics of patients and healthcare workers. 

COVID-19)

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

A case of a readmitted patient who recovered from COVID-19 in Chengdu

Serial CT features in discharged COVID-19 patients with positive RT-PCR re-test

Emergency Use Authorizations. U.S. Food and Drug Administration

Comparison of the Panther Fusion and a laboratory-developed test targeting the envelope gene for detection of SARS-CoV-2

Prolonged persistence of SARS-CoV-2 RNA in body fluids

Dynamic profile of RT-PCR findings from 301 COVID-19 patients in Wuhan, China: A descriptive study

None.