The relationship between SARS-CoV-2 viral load and risk of disease progression remains largely undefined in coronavirus disease 2019 (COVID-19). Here, we quantify SARS-CoV-2 viral load from participants with a diverse range of COVID-19 disease severity, including those requiring hospitalization, outpatients with mild disease, and individuals with resolved infection. We detected SARS-CoV-2 plasma RNA in 27% of hospitalized participants, and 13% of outpatients diagnosed with COVID-19. Amongst the participants hospitalized with COVID-19, we report that a higher prevalence of detectable SARS-CoV-2 plasma viral load is associated with worse respiratory disease severity, lower absolute lymphocyte counts, and increased markers of inflammation, including C-reactive protein and IL-6. SARS-CoV-2 viral loads, especially plasma viremia, are associated with increased risk of mortality. Our data show that SARS-CoV-2 viral loads may aid in the risk stratification of patients with COVID-19, and therefore its role in disease pathogenesis should be further explored.

The relationship between SARS-CoV-2 viral load and risk of disease progression remains largely undefined in coronavirus disease 2019 (COVID-19). We quantified SARS-CoV-2 viral load from participants with a diverse range of COVID-19 severity, including those requiring hospitalization, outpatients with mild disease, and individuals with resolved infection. SARS-CoV-2 plasma RNA was detected in 27% of hospitalized participants and 13% of outpatients diagnosed with COVID-19. Amongst the participants hospitalized with COVID-19, higher prevalence of detectable SARS-CoV-2 plasma viral load was associated with worse respiratory disease severity, lower absolute lymphocyte counts, and increased markers of inflammation, including C-reactive protein and IL-6. SARS-CoV-2 viral loads, especially plasma viremia, were associated with increased risk of mortality. SARS-CoV-2 viral load may aid in the risk stratification of patients with COVID-19 and its role in disease pathogenesis should be further explored.

Coronavirus disease 2019 (COVID‐19) is associated with adverse outcomes, including need for invasive mechanical ventilation and death in people with risk factors. Liver enzyme elevation is commonly seen in this group, but its clinical significance remains elusive. In this study, we calculated the Fibrosis‐4 (FIB‐4) score for a cohort of hospitalized patients with COVID‐19 and assessed its association with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) RNA, inflammatory cytokine levels, and clinical outcome. A total of 202 hospitalized participants who tested positive for SARS‐CoV‐2 by nasopharyngeal sampling were included in this analysis. FIB‐4 was calculated for each participant using the alanine aminotransferase, aspartate aminotransferase, age, and platelet count. We evaluated the association between FIB‐4 and mortality using both multivariate logistic regression and Cox proportional hazards model. Correlations between FIB‐4 and SARS‐CoV‐2 RNA and cytokine levels were evaluated using the Spearman test. Among the 202 participants, 22 died. The median FIB‐4 in participants who survived and died were 1.91 and 3.98 ( P < 0.001 by Mann‐Whitney U test), respectively. Each one‐unit increment in FIB‐4 was associated with an increased odds of death (odds ratio, 1.79; 95% confidence interval, 1.36, 2.35; P < 0.001) after adjusting for baseline characteristics including sex, body mass index, hypertension, diabetes, and history of liver diseases. During hospitalization, FIB‐4 peaked and then normalized in the survival group but failed to normalize in the death group. FIB‐4 was positively correlated with the level of SARS‐CoV‐2 viral load and monocyte‐associated cytokines, especially interleukin‐6 and interferon gamma–induced protein 10. Conclusion: FIB‐4 is associated with mortality in COVID‐19, independent of underlying conditions including liver diseases. FIB‐4 may be a simple and inexpensive approach to risk‐stratify individuals with COVID‐19.