Comparable to NI peoples15,30, DPB4/S167+CD4+ T cells displayed a heavy bias for TRAV35/TRAJ42 gene segments, along with a prominent ‘CXXXNYGGSQGNLIF’ complementarity-determining region (CDR) 3α motif (X denotes any amino acid), and accounted for most of the TCRα repertoire in FN peoples after COVID-19 vaccination or SARS-CoV-2 infection (Fig. 6a). Here, CD4 is linked to COVID-19.