a-c, Spike (a), RBD (b) and NP EPTs (c) in association with overall T cell responses. Red and black data points represent patients with severe and mild symptoms, respectively. n = 42. Spearman’s rank correlation coefficients (R) are shown. d, Comparison of spike EPTs (P < 0.0001), RBD EPTs (P < 0.0001) and NP EPTs (P = 0.0004) for patients with mild symptoms (n = 28) versus severe symptoms (n = 14). Data are presented as medians with interquartile ranges and a Mann-Whitney U-test was used for comparison. Two-tailed P values were calculated. ***P < 0.001; ****P < 0.0001.