SARS-CoV-2 respiratory viral loads and association with clinical and biological features.

Biguenet, A; Bouiller, K; Marty-Quinternet, S; Brunel, A S; Chirouze, C; Lepiller, Q

PURPOSE To determine the distribution of SARS-CoV-2 respiratory viral loads (VL) during the acute phase of infection and their correlation with clinical presentation and inflammation-related biomarkers. METHODS Nasopharyngeal swabs from 453 adult SARS-CoV-2-infected patients from the Department of Infectious Diseases, Besançon, France, were collected at the time of admission or consultation for RT-PCR analysis. Clinical information and concentrations of biological parameters (CRP, fibrinogen, LDH, prealbumin) were noticed. RESULTS Mean respiratory VL homogeneously decreased from 7.2 log10 copies/ml (95%CI: 6.6 to 7.8) on the first day of symptoms until 4.6 log10 copies/ml (95%CI: 3.8 to 5.4) at day 10 (slope=-0.24; R²=0.95). VL were poorly correlated with COVID-19 symptoms and outcome, excepted for dyspnea and anosmia, which were significantly associated with lower VL (p<0.05). CRP, fibrinogen, and LDH concentrations significantly increased over the first 10 days (median CRP concentrations from 36.8 mg/L at days 0-1 to 99.5 mg/L at days 8-10, p<0.01), whereas prealbumin concentrations tended to decrease. CONCLUSION Since SARS-CoV-2 respiratory viral loads regularly decrease in the acute phase of infection, determining the level of VL may help predicting the onset of virus shedding in a specific patient. However, the role of SARS-CoV-2 VL as a biomarker of severity is limited. This article is protected by copyright. All rights reserved.