Understanding viral shedding of severe acute respiratory coronavirus virus 2 (SARS-CoV-2): Review of current literature

Abstract

Objective: Transmission of SARS-CoV-2 has significant implications for hospital infection prevention and control, discharge management, and public health. We reviewed available literature to reach an evidenced-based consensus on the expected duration of viral shedding. Design: We queried four scholarly repositories/search engines for studies reporting SARS-CoV-2 viral shedding dynamics by PCR and/or culture available through September 8, 2020. We calculated the pooled median duration of viral RNA shedding from respiratory and fecal sources. Results: Seventy-seven studies on SARS-CoV-2 were included. All studies reported PCR-based testing and 12 also included viral culture data. The overall pooled median duration of RNA shedding from respiratory sources was 18.4 days (95% CI: 15.5 days - 21.3 days; I2=98.87%, p<0.01) among 28 studies. When stratified by disease severity, the pooled median duration of viral RNA shedding from respiratory sources was 19.8 days (95% CI: 16.2 days – 23.5 days; I2=96.42%, p<0.01) among severely ill patients and 17.2 days (95% CI: 14.0 days - 20.5 days; I2=95.64%, p<0.01) in mild/moderate illness. Viral RNA was detected up to 92 days after symptom onset. Viable virus was isolated by culture from -6 days to 20 days relative to symptom onset. Conclusions: SARS-COV-2 RNA shedding can be prolonged, yet high heterogeneity exists. Detection of viral RNA may not correlate with infectivity since available viral culture data suggests shorter durations of shedding of viable virus. Additional data is needed to determine the duration of shedding of viable virus and the implications for risk of transmission.

Catching a resurgence: Increase in SARS-CoV-2 viral RNA identified in wastewater 48 h before COVID-19 clinical tests and 96 h before hospitalizations

“…The short peak period may also be associated to fecal shedding patterns of the population contributing to the wastewater. It is noted that several current studies investigating fecal shedding timelines and intensity for SARS-CoV-2 may in fact be investigating the sickest of patients in a hospital setting ( Chen et al, 2020 ; Fontana et al, 2020 ), and so patterns may not reflect occurrences in the general population, where a significant quantity of patients will likely suffer from milder symptoms, or no symptoms at all ( Pan et al, 2020 ; Park et al, 2020 ). Furthermore, sicker or elderly patients may in fact “fall off” the wastewater monitoring efforts if bed pans or adult diapers are utilized as part of their treatment and convalescence in a hospital or retirement home ( Coelho et al, 2015 ; Tsang et al, 2017 ).…”

Risk and predictive factors of prolonged viral RNA shedding in upper respiratory specimens in a large cohort of COVID-19 patients admitted to an Italian reference hospital

“…The association between severity of COVID-19 disease and duration of viral RNA shedding has already been widely reported ( Xu et al, 2020 , Du et al, 2020 , Zhou et al, 2020a , Liu et al, 2020a , Zheng et al, 2020 ). Indeed, although several studies have described similar ( To et al, 2020 , Cevik et al, 2020 , Yilmaz et al, 2021 ) or even longer ( Cevik et al, 2020 ) duration of viral RNA shedding in URT in mild compared to severe cases, the majority of reports found that patients with more severe illness shed viral RNA for a longer period of time ( Cevik et al, 2020 , Xu et al, 2020 , Du et al, 2020 , Zhou et al, 2020a , Liu et al, 2020a , Zheng et al, 2020 , Fontana et al, 2020 ). It is worth noting that the definition of severity among these studies is not homogeneous.…”

Understanding the outcomes of COVID-19 – does the current model of an acute respiratory infection really fit?

“…Distribution of mean and maximum recorded shedding periods for SARS-CoV-2 and other respiratory viruses after disease onset. Mean durations of SARs-CoV-2 shedding by PCR in 31 published larger cohort studies (total subjects=4150) [2, 37, 90–97] compared to those of RSV and IAV [1, 7–14]. Solid black lines indicate the mean value of all studies for each virus.…”