The overall aim of this prospective study is to provide an in-depth characterization of clinical and immunological features of patients hospitalized in UZ Leuven because of SARS-CoV-2 infection. For this purpose, clinical data and blood, nasopharyngeal/rectal swab, and if safe, bronchoalveolar lavage (BAL) fluid and lung tissue samples will be collected from PCR- or CT-confirmed COVID-19 patients, with varying degrees of disease severity. Assessed characteristics will be compared between severe and non-severe COVID-19 patients, and between COVID-19 positive and negative ('control') patients.