Severe SARS-CoV-2 alpha variant convalescent patients exhibit worse T cell immune response than those with mild severity disease

COVID-19 convalescents showed T helper and cytotoxic T cells with lower CD127 expression in the severe disease group than those in the mild disease group. Severe COVID-19 convalescents infected with the alpha variant exhibited poorer T cell immune responses against the SARS-CoV-2 wild type, alpha, or omicron variants. Our study provides insights into the differences in T cell phenotypes and immune responses during the contraction phase following SARS-CoV-2 infection across varying disease severities. These findings offer valuable perspectives for advancing future research on SARS-CoV-2 T cell-related immune responses.