Increased risk of severe COVID-19 in hospitalized patients with SARS-CoV-2 Alpha variant infection: a multicentre matched cohort study oleh Guillaume Martin-Blondel, François-Xavier Lescure, Lambert Assoumou, Charlotte Charpentier, Jean-Marc Chapplain, Thomas Perpoint, Gaspard Grouteau, Hugues Cordel, Gilles Pialoux, Jérome Pacanowski, Michael Thy, Adeline Bauvois, Didier Laureillard, Fadia Hamrouni, Michèle Algarte-Genin, Julien Poissy, Diane Descamps, Dominique Costagliola, for the CoCliCo Study Group