Tough

Updated: July 19, 2020

How long do people with COVID-19 shed the virus?

Summary

Viral shedding implies the potential for transmitting the virus and in SARS-CoV-2, viral shedding tends to begin 2 to 3 days before symptom onset and peaks the day before symptom onset [1]. After symptoms onset, viral load steadily decreases [1]. However, both symptomatic and asymptomatic people have been shown to shed the virus [4]. Overall, the viral shedding period has been shown to be 12 days on average, but this can range from 4 days to 34 days [1]. Viral Ribonucleic acid (RNA), single strands containing the genetic coding of the virus, was detected for 20 days in most cases and up to a maximum of 37 days [1]. One study, after screening patients that previously tested positive for COVID-19, states that patients with COVID-19 continue to shed detectable viral RNA for 2 to 4 weeks after resolution of symptoms [2]. It is important to note that the presence of RNA does not always mean the same as infectiousness, as the presence of nucleic acid does not always indicate live virus is present [3]. The percentage of people with SARS-CoV2 that will transmit the virus even after recovery is unknown.

Contingencies

The development of a detailed, robust answer relies on several factors. To provide a detailed REAL Note requires knowing the following:
o  At a population level, longer-term epidemiological research on recovery and viral shedding
o  More conclusive evidence regarding the relationship between severity of illness and viral shedding
o  Nature of immune response and the asymptomatic nature of the disease
o  Prognosis of the COVID-19 in patients with other chronic diseases or conditions

Evidence

Review of Evidence

Resource Type/Source of Evidence Last Updated
Temporal dynamics in viral shedding and transmissibility of COVID-19
— He et al.
Single Study Last Updated: April 14, 2020
Persistent viral RNA shedding after COVID-19 symptomresolution in older convalescent plasma donors
— Hartman et al.
Report Last Updated: May 18, 2020
COVID-19 –What We Know So Far About…Viral Detection
— Publich Health Ontario
Background Information Last Updated: July 4, 2020
SARS-CoV-2 Viral Load in Upper Respiratory Specimens of Infected Patients
— Zou et al.
Rapid Review Last Updated: March 18, 2020
Disclaimer: The summaries provided are distillations of reviews that have synthesized many individual studies. As such, summarized information may not always be applicable to every context. Each piece of evidence is hyperlinked to the original source.

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