Inclusion Criteria:  All adult COVID-19 patients (>18 years) admitted to the ICU between 01/02/2020 and 31/07/2021 with a laboratory confirmation of COVID-19 infection with a positive result on polymerase chain reaction (PCR) assays of nasopharyngeal swab samples or bronchoalveolar lavage  Exclusion Criteria:  All adult patients admitted for other reasons to the ICU (no COVID-19 pneumonia)