CD8A and COVID-19: In patients with long COVID-19, studies have thus far shown mixed results regarding whether effector CD8 T cells are increased or decreased.52–54 Moreover, PD1+ SARS-CoV-2-specific CD8 T cells have been shown to be functional, rather than exhausted, in patients with COVID-19 infection.55 Further validation would be required to confirm the functional status of PD1+ CD8 T cells identified in patients in our study.