Inclusion Criteria:  Admission to ICU and endotracheal intubation/mechanical ventilation for severe COVID-19 infection  Exclusion Criteria:  Age <18 years Pregnancy Patients with a terminal underlying disease who are unlikely to survive until discharge from the hospital Patients with acquired immunodeficiency and ("pre-COVID") lymphocyte Cluster Differentiation 4+ count <50 / μL Patients with COVID-19 who have been transferred from another hospital Patients with a history of allergic reaction Use of prone position to facilitate mechanical ventilation Absence of signed informed consent from a first degree relative