Inclusion Criteria:  patients hospitalized in the ICU with severe acute respiratory syndrome progressive deterioration of the ventilatory status in the first 48 hours in the ICU, which may require mechanical ventilation within this period; confirmed diagnosis of COVID-19 within 3 days of ICU admission; acceptance to participate.  Exclusion Criteria:  relevant immunodeficiency (decompensated HIV, aggressive immunosuppression, terminal cancer) decompensated systemic disease before the onset of COVID-19.