An international team of researchers from the Institute for Research in Biomedicine, affiliated to the Università della Svizzera italiana, has deciphered the T cell responses occurring during COVID-19 infection at single-cell resolution. This study, which was performed at the Center of Medical Immunology under the leadership of Prof. Federica Sallusto, included collaborations with clinical institutions from Ticino and Italy: Ente Ospedaliero Cantonale (EOC), the Clinica Luganese Moncucco, the Policlinico S. Matteo in Pavia, and INGM Milano, is published in the current issue of Science.