Although we could not perform polyfunctional cytotoxic analysis of spike-specific CD8+ T cells from COVID-19 patients with severe disease at three weeks post natural infection because of the low frequency of spike-specific CD8+ T cells (Supplemental Figure 4A), we detected polyfunctional cytotoxic CD8 T cells in the recovered donors at three weeks post natural infection (Supplemental Figure 4B). This evidence concerns the gene CD8A and infection.