SARS-CoV-2 Viral Load in the Pulmonary Compartment of Critically Ill COVID-19 Patients Correlates with Viral Serum Load and Fatal Outcomes

Mario Ynga-Durand; Henrike Maaß; Marko Milošević; Fran Krstanović; Marina Pribanić Matešić; Stipan Jonjić; Alen Protić; Ilija Brizić; Alan Šustić; Luka Čičin-Šain

doi:10.3390/v14061292

SARS-CoV-2 Viral Load in the Pulmonary Compartment of Critically Ill COVID-19 Patients Correlates with Viral Serum Load and Fatal Outcomes

Viruses. 2022 Jun 14;14(6):1292. doi: 10.3390/v14061292.

Authors

Affiliations

¹ Helmholtz Center for Infection Research, Department of Viral Immunology, 38124 Braunschweig, Germany.
² Department of Anesthesiology, Reanimation, Intensive Care and Emergency Medicine, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia.
³ Center for Proteomics, Faculty of Medicine, University of Rijeka, 51000 Rijeka, Croatia.
⁴ Department of Clinical Medical Science II, Faculty of Health Studies, University of Rijeka, 51000 Rijeka, Croatia.
⁵ German Centre for Infection Research (DZIF), Partner Site Hannover/Braunschweig, 38124 Braunschweig, Germany.
⁶ Centre for Individualised Infection Medicine (CiiM), A Joint Venture of Helmholtz Centre for Infection Research and Hannover Medical School, 30625 Hannover, Germany.

Abstract

While SARS-CoV-2 detection in sputum and swabs from the upper respiratory tract has been used as a diagnostic tool, virus quantification showed poor correlation to disease outcome and thus, poor prognostic value. Although the pulmonary compartment represents a relevant site for viral load analysis, limited data exploring the lower respiratory tract is available, and its association to clinical outcomes is relatively unknown. Using bronchoalveolar lavage (BAL) and serum samples, we quantified SARS-CoV-2 copy numbers in the pulmonary and systemic compartments of critically ill patients admitted to the intensive care unit of a COVID-19 referral hospital in Croatia during the second and third pandemic waves. Clinical data, including 30-day survival after ICU admission, were included. We found that elevated SARS-CoV-2 copy numbers in both BAL and serum samples were associated with fatal outcomes. Remarkably, the highest and earliest viral loads after initiation of mechanical ventilation support were increased in the non-survival group. Our results imply that viral loads in the lungs contribute to COVID-19 disease severity, while blood titers correlate with lung virus titers, albeit at a lower level. Moreover, they suggest that BAL SARS-CoV-2 copy number quantification at ICU admission may provide a predictive parameter of clinical COVID-19 outcomes.

Keywords: COVID-19; SARS-CoV-2; bronchoalveolar lavage; critical care; qPCR.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

COVID-19*
Critical Illness
Humans
Lung
SARS-CoV-2*
Viral Load

Grants and funding

This research was supported by the Project “Virological and immunological determinants of COVID-19 pathogenesis–lessons to get prepared for future pandemics (KA1-Co-02 “COVIPA”)”, a grant from the Helmholtz Association’s Initiative and Networking Fund. It was funded by the German Scientific Foundation (DFG) through the RESIST Excellence cluster (EXC 2155, project B6), and the Helmholtz Association EU partnering grant PIE-0008. This work has been supported in part by the Croatian Science Foundation under the project IP-CORONA-04-2073 (I.B.).