Inclusion Criteria:  Adult patient (> 18 years) PCR (polymerase chain reaction) -confirmed SARS-CoV-2 infections based on nasopharyngeal swab (NPS), oropharyngeal swab (OPS), tracheal aspirate (TA), bronchial aspirate (BA), or bronchoalveolar lavage fluid (BALF) within 14 days prior to ICU admission or within 72 hours following ICU admission due to severe COVID-19 infection Radiographic imaging consistent with SARS-CoV-2 infection (e.g. atypical pneumonia, organizing pneumonia, ground glass opacities) or ARDS within 7 days of diagnosis of SARS-CoV-2 infection  Exclusion Criteria:  Patients with a diagnosis of invasive aspergillosis/detection of Aspergillus spp. by culture from sputum, TA, BA, or BALF or positive GM from serum, TA, or BALF at baseline (=ICU admission) History of invasive aspergillosis within the prior six months Patients that are being treated with mold-active antifungal agents for invasive aspergillosis or another invasive fungal infection Patients that are being treated with mold-active antifungal agents for invasive aspergillosis or another invasive fungal infection Death or transfer to general ward within 48 hours of ICU admission Antifungal prophylaxis other than posaconazole (e.g. inhaled amphotericin B)