CD4 and infection: Our data indicated that CD4+ and CD8+ T cells in the peripheral blood early after infection might be a good predictor of prognosis and thereby lead to appropriate alternative treatment strategies for COVID-19 due to the significantly high correlation of CD4+ and CD8+ T cells with SARS-CoV-2-specific IFNγ+CD4+ and IFNγ+CD8+ T cells, respectively.