Oral Shedding of Torque Teno Virus (TTV) in COVID-19 patients - possible biomarker of severity

Abstract

COVID-19 is a disease caused by the SARS-CoV-2, with mild, moderate and severe forms, the latter of which can lead to death as a result of clinical impairment. Saliva has been presented as a less invasive alternative for detecting SARS-CoV-2, also presenting the possibility of analyzing inflammatory and immunological biomarkers that may be related to both the diagnosis and prognosis of the disease. In addition to chemokines, cytokines and antibodies, the Torque Teno Virus (TTV), a small, non-pathogenic and ubiquitous single-stranded virus, has proven useful as a biomarker of immunocompetence in different situations, including inflammatory diseases such as COVID-19. In this project we will evaluate the oral shedding of TTV in the saliva of patients with COVID-19, comparing with clinical parameters of severity (mild, moderate and severe), the levels of salivary and plasma inflammatory and immunological biomarkers and the outcome of these patients, in order to investigate its potential use as a biomarker of severity and prognosis. Saliva samples will be used to evaluate the inflammatory immune response of patients diagnosed with COVID-19, in its mild, moderate and severe forms, as well as to evaluate the excretion kinetics of TTV and SARS-CoV-2 at different times, with weekly collections, until the outcome (medical discharge or death). The humoral immune response will also be evaluated, by detecting IgM, IgG and IgA antibodies, at the different times analyzed.