CD8A and COVID-19: In mild COVID-19, a more potent adaptive immune response to SARS-CoV-2 was observed, as evidenced by the presence of CD8+ T-cells with tissue-resident features displaying clonal expansion and increased effector function.14 Subsequently, Bost et al. monitored viral sequencing reads at single-cell level to separate infected from bystander cells and investigated virus-induced transcriptional changes.