Initial SARS-CoV-2 viral load is associated with disease severity: a retrospective cohort study

Abstract Background We assessed the association between SARS-CoV-2 viral load and hospital-, ICU admission and in-hospital mortality. Methods All SARS-CoV-2 positive persons with a combined nasopharyngeal (NP) and oropharyngeal (OP) swab that was collected between March 17, 2020, and March 31, 2021, in Public Health testing facilities were included. Results From 20.207 SARS-CoV-2 positive persons, 310 (1.5%) were hospitalized within 30 days. High viral loads (Cp < 25) were associated with an increased risk of hospitalization as compared to low viral loads (Cp > 30), ORadjusted [95%CI]: 1.57 [1.11-2.26], adjusted for age and sex. The same association was seen for ICU admission, ORadjusted [95%CI]: 7.06 [2.15-43.57]. The median [IQR] Cp-value of the 17 patients who deceased in-hospital was significantly lower compared to the 226 survivors: 22.7 [3.4] vs. 25.0 [5.2]. Discussion Higher initial SARS-CoV-2 viral load is associated with an increased risk of hospital admission, ICU admission, and in-hospital mortality. Our findings emphasize the added value of reporting SARS-CoV-2 viral load or Ct/Cp-values to identify persons who are at the highest risk of adverse outcomes such as hospital or ICU admission and who therefore may benefit from more intensive monitoring or early initiation of antiviral therapy.