CD4 and COVID-19: SARS-CoV-2-specific CD8+ T cells are also detectable in acute COVID-19 cases, albeit less consistently than CD4+ T cells, and their presence was also correlated with a better outcome of COVID-19 (Bert et al., 2021; Moderbacher et al., 2020; Sekine et al., 2020; Tan et al., 2021).