The Relationship Between COVID-19 Viral Load and Disease Severity: A Systematic Review

Overview

Journal Immun Inflamm Dis

Specialties Allergy & Immunology
Infectious Diseases

Date 2021 Dec 14

PMID 34904379

Citations 73

Authors

Omid Dadras

Amir M Afsahi

Zahra Pashaei

Hengameh Mojdeganlou

Amirali Karimi

Pedram Habibi

Alireza Barzegary

Amirata Fakhfouri

Pegah Mirzapour

Nazanin Janfaza

Soheil Dehghani

Fatemeh Afroughi

Mohsen Dashti

Sepideh Khodaei

Esmaeil Mehraeen

Fabricio Voltarelli

Jean-Marc Sabatier

SeyedAhmad SeyedAlinaghi

Affiliations

Soon will be listed here.

Abstract

Introduction: Patients with COVID-19 may present different viral loads levels. However, the relationship between viral load and disease severity in COVID-19 is still unknown. Therefore, this study aimed to systematically review the association between SARS-CoV-2 viral load and COVID-19 severity.

Methods: The relevant studies using the keywords of "COVID-19" and "viral load" were searched in the databases of PubMed, Scopus, Google Scholar, and Web of Science. A two-step title/abstract screening process was carried out and the eligible studies were included in the study.

Results: Thirty-four studies were included from the initial 1015 records. The vast majority of studies have utilized real-time reverse transcription-polymerase chain reaction of the nasopharyngeal/respiratory swabs to report viral load. Viral loads were commonly reported either as cycle threshold (C ) or log RNA copies/ml.

Conclusion: The results were inconclusive about the relationship between COVID-19 severity and viral load, as a similar number of studies either approved or opposed this hypothesis. However, the studies denote the direct relationship between older age and higher SARS-CoV-2 viral load, which is a known risk factor for COVID-19 mortality. The higher viral load in older patients may serve as a mechanism for any possible relationships between COVID-19 viral load and disease severity. There was a positive correlation between SARS-CoV-2 viral load and its transmissibility. Nonetheless, further studies are recommended to precisely characterize this matter.

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