CD8A and COVID-19: CD4+, but not CD8+ T cells or B cells, were found to have strong association with COVID-19 severity, with rapid induction of SARS-CoV-2-specific CD4+ T cells being associated with mild disease and accelerated viral clearance, while delayed or absence of SARS-CoV-2-specific CD4+ T cells being associated with severe or fatal COVID-19 (35, 36).