Impact of Severe Acute Respiratory Syndrome Coronavirus 2 Viral Load on Risk of Intubation and Mortality Among Hospitalized Patients With Coronavirus Disease 2019

Clin Infect Dis. 2021 Dec 6;73(11):e4197-e4205. doi: 10.1093/cid/ciaa851.


Background: Patients hospitalized with coronavirus disease 2019 (COVID-19) frequently require mechanical ventilation and have high mortality rates. However, the impact of viral burden on these outcomes is unknown.

Methods: We conducted a retrospective cohort study of patients hospitalized with COVID-19 from 30 March 2020 to 30 April 2020 at 2 hospitals in New York City. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load was assessed using cycle threshold (Ct) values from a reverse transcription-polymerase chain reaction assay applied to nasopharyngeal swab samples. We compared characteristics and outcomes of patients with high, medium, and low admission viral loads and assessed whether viral load was independently associated with intubation and in-hospital mortality.

Results: We evaluated 678 patients with COVID-19. Higher viral load was associated with increased age, comorbidities, smoking status, and recent chemotherapy. In-hospital mortality was 35.0% (Ct <25; n = 220), 17.6% (Ct 25-30; n = 216), and 6.2% (Ct >30; n = 242) with high, medium, and low viral loads, respectively (P < .001). The risk of intubation was also higher in patients with a high viral load (29.1%) compared with those with a medium (20.8%) or low viral load (14.9%; P < .001). High viral load was independently associated with mortality (adjusted odds ratio [aOR], 6.05; 95% confidence interval [CI], 2.92-12.52) and intubation (aOR, 2.73; 95% CI, 1.68-4.44).

Conclusions: Admission SARS-CoV-2 viral load among hospitalized patients with COVID-19 independently correlates with the risk of intubation and in-hospital mortality. Providing this information to clinicians could potentially be used to guide patient care.

Keywords: SARS-CoV-2; coronavirus disease 2019; hospitalized patients; outcomes; viral load.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • COVID-19*
  • Humans
  • Intubation, Intratracheal
  • Retrospective Studies
  • SARS-CoV-2*
  • Viral Load