Persistent Detection and Infectious Potential of SARS-CoV-2 Virus in Clinical Specimens from COVID-19 Patients

Abstract

The Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) that emerged in December 2019 as the causative agent of Coronavirus 2019 (COVID-19) and was declared a pandemic by the World Health Organization in March 2020 has several distinctive features, including extensive multiorgan involvement with a robust systemic inflammatory response, significant associated morbidity and mortality, and prolonged persistence of viral RNA in the clinical specimens of infected individuals as detected by Reverse Transcription Polymerase Chain Reaction (RT-PCR) amplification. This review begins with an overview of SARS-CoV-2 morphology and replication and summarizes what is known to date about the detection of the virus in nasal, oropharyngeal, and fecal specimens of patients who have recovered from COVID-19, with a focus on the factors thought to contribute to prolonged detection. This review also provides a discussion on the infective potential of this material from asymptomatic, pre-symptomatic, and convalescing individuals, to include a discussion of the relative persistence and infectious potential of virus in clinical specimens recovered from pediatric COVID-19 patients.

Keywords: COVID-19; SARS-CoV-2; coronavirus; shedding.

Figure 1

Entry and replication of SARS-CoV-2 in host cells. Reproduced with kind permission from Shailendra Saxena of King George’s Medical University (KGMU), Lucknow, India [27].

Figure 2

Duration of SARS-CoV-2 RT-PCR positivity in respiratory specimens reported in studies of adult COVID-19 patients cited in this review. Vertical lines represent the median duration, and the boxes represent the interquartile range. The study reference numbers are in parentheses. See text for additional details.

Figure 3

Summary of the Centers for Disease Control and Prevention (CDC) guidelines for the discontinuation of transmission-based precautions and disposition of patients with COVID-19 in healthcare settings. Recognizing that recovered COVID-19 patients may persistently shed inert non-infectious virus into clinical specimens, the CDC generally recommends a symptom-based rather than a test-based approach for symptomatic individuals [70]. (NA: Not applicable).

Figure 4

Duration of SARS-CoV-2 RT-PCR positivity in respiratory and fecal specimens reported in studies of pediatric COVID-19 patients cited in this review. The medians are indicated by a solid vertical line, and the means are indicated by a dashed vertical line. A solid box indicates interquartile range, and a dashed box indicates range. Unshaded boxes indicate respiratory specimens, and stippled boxes indicate fecal specimens. The study reference numbers are in parentheses. See text for additional details.