Baseline plasma SARS-CoV-2 RNA detection predicts an adverse COVID-19 evolution in moderate to severe hospitalized patients

Background: SARS-CoV-2 is a single-stranded RNA virus, known to be the causative agent of COVID-19. As the resulting disease shows a very heterogeneous range of clinical manifestations, the identification of early biomarkers allowing patients stratification according to the expected disease severity is still an unmet clinical need. Methods: In this observational prospective cohort study, 137 consecutive patients, testing positive for SARS-CoV-2 infection by nasopharyngeal swab RT-PCR or antigenic test, were enrolled to evaluate their plasma viral load at the time of hospitalization. Results: Even if all of them had a molecular diagnosis of COVID-19, only 29 patients showed a detectable plasma SARS-CoV-2 RNAemia. Such viremic patients also showed other clinical and laboratory finding alterations (increased troponin I, IL-6, RDW-CV, and creatinine levels along with decreased platelet count and glomerular filtration rate). A plasma detectable RNA viral load predicted in hospital death or ICU admission with an odds ratio of 3.53 (CI: 1.44-8.64, P=0.0058), while the lack of a detectable viral load was associated with a faster recovery, with an odds ratio of 4.06 (CI: 1.72-9.59, P=0.0014). These findings were confirmed in multivariate models including age, sex and baseline National Early Warning Score 2 and arterial oxygen tension over inspired oxygen fraction ratio. Conclusions: Our data thus suggest that plasma viral RNA load at the time of hospital admission could represent a useful independent biomarker allowing early patients' stratification according to the expected disease evolution, and driving clinical decisions tailored on the specific needs of the individual patient.