Association between upper respiratory tract viral load, comorbidities, disease severity and outcome of patients with SARS-CoV-2 infection

Background There is limited information on the association between upper respiratory tract (URT) viral loads, host factors, and disease severity in SARS-CoV-2–infected patients. Methods We studied 1122 patients (mean age, 46 years) diagnosed by polymerase chain reaction (PCR). URT viral load, measured by PCR cycle threshold, was categorized as high, moderate, or low. Results There were 336 (29.9%) patients with comorbidities; 309 patients (27.5%) had high, 316 (28.2%) moderate, and 497 (44.3%) low viral load. In univariate analyses, compared to patients with moderate or low viral load, patients with high viral load were older, more often had comorbidities, developed Symptomatic disease (COVID-19), were intubated, and died. Patients with high viral load had longer stay in intensive care unit and longer intubation compared to patients with low viral load (P values Conclusions URT viral load could be used to identify patients at higher risk for morbidity or severe outcome.