SARS-CoV-2 Viral Load in Stool and Nasopharyngeal/Oropharyngeal Samples: Implications for Clinical Progression in Severe COVID-19 Patients.

The SARS-CoV-2 RNA load in different specimens has been analyzed to evaluate its correlation with disease outcomes and other factors. However, conflicting results have emerged due to variations in study design. This study examines the impact of viral load in stool and nasopharyngeal/oropharyngeal (NP) specimens on the clinical outcomes of hospitalized patients with severe COVID-19. Forty-six intensive care unit (ICU) patients with COVID-19 were enrolled between September 2020 and March 2021. NP swab and stool samples were collected at admission and at clinical outcome, and viral load was quantified using RT-qPCR. All patients had positive NP RNA at admission, with 41 (89.1%) also testing positive in stool samples. At the time of clinical outcome, 67.4% of NP samples and 45.7% of stool samples remained positive. Patients without gastrointestinal symptoms had a higher stool viral load at admission. Additionally, a greater NP viral load at admission was associated with unfavorable outcomes, whereas patients with diarrhea exhibited a more rapid decline in NP viral load. These preliminary findings suggest that diarrhea is associated with faster NP viral load reduction. Furthermore, viral load clearance was more efficient in stool samples than in respiratory specimens. These results highlight the relationship between viral load and COVID-19 severity.