The median fraction of SARS-CoV-2-specific CD4+ T cells among CD4+ T cells were 0.05% (IQR 0.019%–0.1%), 0.04% (IQR 0.012%–0.084%), 0.08% (IQR 0.02%–0.17%), 0.08% (IQR 0.03%–0.12%), 0.03% (IQR 0.01%–0.12%), and 0.05% (IQR 0.02%–0.11%) in the CAD, hypertension, DM, CRD, cancer, and health group, respectively (Supplementary Table 8). Here, CD4 is linked to cancer.