Detection of SARS-CoV-2 in Different Types of Clinical Specimens

Detection of SARS-CoV-2 in Different Types of Clinical Specimens. Jefferson T, Heneghan C.,

Published on July 15, 2020

Reference Wang W, Xu Y, Gao R, Lu R, Han K, Wu G, et al. Detection of SARS-CoV-2 in Different Types of Clinical Specimens. Detection of SARS-CoV-2 in Different Types of Clinical Specimens. JAMA. 2020 May 12; 323(18): 1843–1844.
Study type
Country China
Setting Sundry
Funding Details National Key Research and Development Program of China and National Major Project for Control and Prevention of Infectious Disease in China
Transmission mode Droplets, Orofecal, contact, person to person, bloodborne

Bottom Line

In this case series from China, two stool specimens out of 44 positives contained live virus, suggesting that orofecal transmission is possible. Transmission of the virus by respiratory and extra respiratory routes may help explain the rapid spread of disease.

Evidence Summary

SARs-CoV-2 was detected in all types of specimens except urine.

Sputum and airways specimens were the most frequent with nasal swabs having the lowest PCR cycle threshold indicating the highest copies of viral nucleic material. Of note, there were three blood detections (viraemia) and four SARS-CoV-2 positive fecal specimens with high copy numbers cultured and observed under the microscope. Two out of four had live virions but they came from patients with no diarrhoea.

Twenty patients had two to six specimens collected simultaneously. Viral RNA was detected in single specimens from six patients (respiratory specimens, feces, or blood), while seven patients excreted virus in respiratory tract specimens and in feces (n = 5) or blood (n = 2). 

What did they do?

This letter to Editor reports the results of the analysis of 1,070 specimens from pharyngeal swabs (1  to 3 days after admission), blood, sputum, feces, urine, nasal samples, bronchoalveolar lavage fluid and fibre bronchoscope brush biopsy from patients on the basis of clinical indications from three hospitals in the Hubei and Shandong provinces and Beijing, China, from January 1st to February 17th 2020. The specimens came from 205 patients aged mean 44 (5-67 years).

Study reliability

Testing of specimens from multiple sites may improve the sensitivity and reduce false-negative test results. 

Clearly defined setting Demographic characteristics described Follow-up length was sufficient Transmission outcomes assessed Main biases are taken into consideration
Unclear * Yes Unclear ** Yes Partly
* The information to correlate specimen positivity with the clinical course is lacking, we only know that 19% of patients had serious disease
** No transmission or contact information is reported either

What else should I consider?

This is a potentially an important study which needs replication

About the authors