CD8A and COVID-19: However, when comparing the exhaustion scores of all BAL-derived CD8+ T cells between the conditions and the outcomes of SARS-CoV-2 infection, the group of severely infected individuals and the group that succumbed to COVID-19 clearly displayed higher exhaustion scores than the group with mild infection or the group that recovered from SARS-CoV-2 infection, respectively (Figures 2J and S2H).