IL10 and COVID-19: The importance of IL-10 and IFN-γ production by T cells has also been highlighted by two recent works: such a functional T cell profile was demonstrated to be defective in severe COVID-19 (30), while the presence of IL-10–producing spike-specific T cells is characteristic of individuals with hybrid SARS-CoV-2 immunity (29) who demonstrate a robust immunity from reinfection (38, 39).