SARS-CoV-2 viral load is associated with increased disease severity and mortality

Fajnzylber, Jesse; Regan, James; Coxen, Kendyll; Corry, Heather; Wong, Colline; Rosenthal, Alexandra; Worrall, Daniel; Giguel, Francoise; Piechocka-Trocha, Alicja; Atyeo, Caroline; Fischinger, Stephanie; Chan, Andrew; Flaherty, Keith T.; Hall, Kathryn; Dougan, Michael; Ryan, Edward T.; Gillespie, Elizabeth; Chishti, Rida; Li, Yijia; Jilg, Nikolaus; Hanidziar, Dusan; Baron, Rebecca M.; Baden, Lindsey; Tsibris, Athe M.; Armstrong, Katrina A.; Kuritzkes, Daniel R.; Alter, Galit; Walker, Bruce D.; Yu, Xu; Li, Jonathan Z.

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.