CD4 and cancer: By day 90, the SARS-CoV-2-specific CD4+ T cell responses (OX40+ CD137+) were detected in 21 (100%) of 21 in the CAD group, 31 (86.1%) of 36 in the hypertension group, 21 (95.5%) of 22 in the DM group, 18 (100%) of 18 in the CRD group, 8 (88.9%) of 9 in the cancer group versus 50 (89.3%) of 56 in health control (Supplementary Table 7).