COVID-19 salivary signature: diagnostic and research opportunities

Abstract

The COVID-19 (caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)) epidemic started in Wuhan (Hubei Province, China) in mid-December 2019 and quickly spread across the world as a pandemic. As a key to tracing the disease and to implement strategies aimed at breaking the chain of disease transmission, extensive testing for SARS-CoV-2 was suggested. Although nasopharyngeal/oropharyngeal swabs are the most commonly used biological samples for SARS-CoV-2 diagnosis, they have a number of limitations related to sample collection and healthcare personnel safety. In this context, saliva is emerging as a promising alternative to nasopharyngeal/oropharyngeal swabs for COVID-19 diagnosis and monitoring. Saliva collection, being a non-invasive approach with possibility for self-collection, circumvents to a great extent the limitations associated with the use of nasopharyngeal/oropharyngeal swabs. In addition, various salivary biomarkers including the salivary metabolomics offer a high promise to be useful for better understanding of COVID-19 and possibly in the identification of patients with various degrees of severity, including asymptomatic carriers. This review summarises the clinical and scientific basis for the potential use of saliva for COVID-19 diagnosis and disease monitoring. Additionally, we discuss saliva-based biomarkers and their potential clinical and research applications related to COVID-19.

Performance of at-home self-collected saliva and nasal-oropharyngeal swabs in the surveillance of COVID-19

“…The use of saliva to detect SARS-CoV-2 has been extensively analyzed by different authors, showing that saliva can be used as an alternative sample to nasopharyngeal swabs for COVID-19 molecular diagnosis [9,10]. The sensitivity found in their studies varied from 81% to 100% [11,12,[17][18][19][20][21].…”

“…Recently, publications have been shown a similar sensitivity between saliva samples and nasal swabs collected by health-care workers and those collected by a patient for COVID-19 molecular diagnosis, thus providing an important background for the choice of this strategy for surveillance of COVID-19 [6][7][8]. Saliva sampling has been described as a good alternative for SARS-CoV-2 detection, showing additional advantages compared to swab collection [9][10][11][12]. Saliva collection does not cause discomfort or nasal bleeding to patients and does not require swab collectors or personal protective equipment, which are currently in short-supply in the market [3].…”

Performance of At-Home Self-Collected Saliva and Nasal-Oropharyngeal Swabs in the Surveillance of COVID-19

“…secondly, presence in the blood and gingival crevicular fluid; and thirdly, through salivary gland infection, with subsequent release of viral particles into the saliva via salivary ducts (10,24,25). It is believed that the highest viral concentration observed in saliva is is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint…”

“…The copyright holder for this this version posted October 27, 2020. ; https://doi.org/10.1101/2020. 10…”

“…Saliva collection does not cause discomfort or nasal bleeding to patients, does not require swab collectors or personal protective equipment, which are currently in short-supply in the market (3). In addition, saliva allows examination of several biomarkers, which could be useful as molecular signatures for patient stratification regarding infection severity (10,13,14).…”