Systematic Reviews
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Crit Care Med. Jul 9, 2021; 10(4): 132-150
Published online Jul 9, 2021. doi: 10.5492/wjccm.v10.i4.132
SARS-CoV-2 (COVID-19), viral load and clinical outcomes; lessons learned one year into the pandemic: A systematic review
Santosh Shenoy
Santosh Shenoy, Department of General and Colorectal Surgery, KCVA and University of Missouri at Kansas City, Missouri, MO 64128, United States
Author contributions: Shenoy S designed the study, performed the literature search, wrote and analyzed the data, revised and approved the final manuscript.
Conflict-of-interest statement: The author declares that he has no competing interests.
PRISMA 2009 Checklist statement: The author has read the PRISMA 2009 checklist, and the manuscript was prepared and revised according to the PRISMA 2009 checklist.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Noncommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Santosh Shenoy, MD, Professor, Department of General and Colorectal Surgery, KCVA and University of Missouri at Kansas City, 4801 E Linwood Blvd., Missouri, MO 64128, United States. shenoy2009@hotmail.com
Received: February 5, 2021
Peer-review started: February 5, 2021
First decision: March 17, 2021
Revised: March 21, 2021
Accepted: June 15, 2021
Article in press: June 15, 2021
Published online: July 9, 2021
Processing time: 151 Days and 22.7 Hours
ARTICLE HIGHLIGHTS
Research background

High viral load has an implication in the clinical outcomes in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. At present there is no Food and Drug Administration Emergency Use Authorization for quantitative viral load assay in the current pandemic. Currently the coronavirus disease 2019 (COVID-19) tests are reported as a binary assessment of either positive or negative test.

Research motivation

The intent of this research is to identify whether quantitative SARS-CoV-2 viral load assay correlates with severity of infection and mortality?

Research objectives

To assess high viral load and its association with the severity, mortality, infectiousness in COVID-19 infections.

Research methods

A systematic literature search was undertaken for a period between December 30, 2019 to December 31, 2020 in PubMed/MEDLINE using combination of terms “COVID-19, SARS-CoV-2, Ct values, Log10 copies, quantitative viral load, viral dynamics, kinetics, association with severity, sepsis, mortality and infectiousness’’. Data on age, number of patients, sample sites, real time reverse transcriptase polymerase chain reaction (RT-PCR) targets, disease severity, intensive care unit admission, mortality and conclusions of the studies was extracted, organized and is analyzed.

Research results

High SARS-CoV-2 viral load was found to be an independent predictor of disease severity and mortality in high proportion of studies, and may be useful in predicting the clinical course and prognosis of patients with COVID-19.

Research conclusions

There is a wide heterogeneity in fluid samples and different phases of the disease and these data should be interpreted with caution and only considered as trends. In aggregate, these observations support the hypothesis of checking and reporting viral load by quantitative RT-PCR, instead of binary assessment of a test being positive or negative.

Research perspectives

In future, longitudinal studies with viral load should be monitored and analyzed, so it can be considered in interpretation of outcome data. It may also be a guiding principle for therapy and infection control policies for current and future pandemics.