Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection platforms currently report qualitative results. However, technology based on RT-PCR allows for calculation of viral load, which is associated with transmission risk and disease severity in other viral illnesses. 1 Viral load in COVID-19 might correlate with infectivity, disease phenotype, morbidity, and mortality. To date, no studies have assessed the association between viral load and mortality in a large patient cohort. 2–4 To our knowledge, we are the first to report on SARS-CoV-2 viral load at diagnosis as an independent predictor of mortality in a large hospitalised cohort (n= 1145).

We prospectively evaluated nasopharyngeal swab samples for SARS-CoV-2 by real-time RT-PCR (Roche cobas 6800; Roche, Basel, Switzerland). Positive samples were assessed by a laboratory-developed quantitative RT-PCR test approved for clinical use5 and viral loads were calculated with standard curves (full method provided in the appendix [pp 1–2]).