CD4 and COVID-19: There was a statistically significant correlation of TRDV1 focusing with CD4+ and CD8+ TRB focusing (Fig. 4E), but in contrast to TRB or IGH sequences (Fig. 3E and SI Appendix, Table S3), very few TRDV1 sequences were shared across donors, and none was significantly enriched in SARS-CoV-2–exposed individuals, suggesting that the Vδ1 responses in COVID-19 are almost exclusively private.