Table 4.
Median (IQR) antibody (IgG BAU/ml) to nucleocapsid proteins (NP), spike protein, and receptor-binding domain (RBD) by time since vaccination dose by age cohort
| 30–50 years | 70 + years | pa | |
|---|---|---|---|
| N | 344 | 861 | |
| 3 Weeks Post 1st Dose | |||
| n (%) with a result | 41 (11.9) | 43 (5.0) | <0.0001 |
| NP | |||
| Median [IQR] BAU/mL | 3.08 [2.33, 4.98] | 3.29 [2.24, 5.64] | 0.48 |
| n (%) Positive | 1 (2.4) | 3 (7.0) | 0.62 |
| Spike | |||
| Median [IQR] BAU/mL | 313 [189, 805] | 41 [15, 230] | <0.0001 |
| n (%) Positive | 40 (97.6) | 36 (83.7) | 0.058 |
| RBD | |||
| Median [IQR] BAU/mL | 219 [54, 516] | 45 [16, 187] | 0.0012 |
| n (%) Positive | 35 (85.4) | 26 (60.5) | 0.014 |
| Spike AND RBD positiveb | 35 (85.4) | 26 (60.5) | 0.014 |
| Pre 2nd Dose | |||
| n (%) with a result | 262 (76.2) | 707 (82.1) | 0.020 |
| NP | |||
| Median [IQR] BAU/mL | 3.38 [2.13, 5.11] | 2.57 [1.67, 4.23] | <0.0001 |
| n (%) Positive | 8 (3.1) | 18 (2.5) | 0.66 |
| Spike | |||
| Median [IQR] BAU/mL | 90 [40, 307] | 25 [11, 65] | <0.0001 |
| n (%) Positive | 251 (95.8) | 519 (73.4) | <0.0001 |
| RBD | |||
| Median [IQR] BAU/mL | 83 [40, 216] | 26 [10, 68] | <0.0001 |
| n (%) Positive | 218 (83.2) | 321 (45.4) | <0.0001 |
| Spike AND RBD positiveb | 218 (83.2) | 320 (45.3) | <0.0001 |
| 2 Weeks Post 2nd Dose | |||
| n (%) with a result | 269 (78.2) | 737 (85.6) | 0.0026 |
| NP | |||
| Median [IQR] BAU/mL | 3.32 [2.48, 5.19] | 3.32 [2.33, 4.94] | 0.38 |
| n (%) Positive | 6 (2.2) | 23 (3.1) | 0.53 |
| Spike | |||
| Median [IQR] BAU/mL | 2359 [2094, 2359] | 1966 [1065, 2359] | <0.0001 |
| n (%) Positive | 268 (99.6) | 726 (98.5) | 0.20 |
| RBD | |||
| Median [IQR] BAU/mL | 5180 [2690, 8067] | 2096 [837, 4726] | <0.0001 |
| n (%) Positive | 269 (100) | 722 (98.0) | 0.015 |
| Spike AND RBD positiveb | 268 (99.6) | 722 (98.0) | 0.084 |
| 12 Weeks Post 2nd Dose | |||
| # (%) with a result | 241 (70.1) | 699 (81.2) | <0.0001 |
| NP | |||
| Median [IQR] BAU/mL | 3.71 [2.73, 5.83] | 3.82 [2.66, 5.74] | 0.90 |
| n (%) Positive | 6 (2.5) | 22 (3.1) | 0.83 |
| Spike | |||
| Median [IQR] BAU/mL | 670 [394, 1177] | 488 [218, 1025] | <0.0001 |
| n (%) Positive | 241 (100) | 689 (98.6) | 0.073 |
| RBD | |||
| Median [IQR] BAU/mL | 637 [360, 1295] | 387 [187, 975] | <0.0001 |
| n (%) Positive | 240 (99.6) | 673 (96.3) | 0.059 |
| Spike AND RBD positiveb | 240 (99.6) | 673 (96.3) | 0.059 |
| 24 Weeks Post 2nd Dose | |||
| # (%) with a result | 231 (67.2) | 696 (80.8) | <0.0001 |
| NP | |||
| Median [IQR] BAU/mL | 4.12 [2.96, 6.26] | 4.38 [2.98, 6.32] | 0.69 |
| n (%) Positive | 6 (2.6) | 19 (2.7) | 0.99 |
| Spike | |||
| Median [IQR] BAU/mL | 337 [181, 728] | 235 [103, 570] | <0.0001 |
| n (%) Positive | 231 (100) | 682 (98.0) | 0.027 |
| RBD | |||
| Median [IQR] BAU/mL | 242 [162, 588] | 206 [106, 514] | 0.00036 |
| n (%) Positive | 230 (99.6) | 650 (93.4) | <0.0001 |
| Spike AND RBD positiveb | 230 (99.6) | 650 (93.4) | <0.0001 |
| 36 Weeks Post 2nd Dose | |||
| n (%) with a result | 215 (62.5) | 690 (80.1) | <0.0001 |
| NP | |||
| Median [IQR] BAU/mL | 5.53 [3.69, 13.4] | 4.72 [3.08, 7.64] | <0.0001 |
| n(%) Positive | 25 (11.6) | 32 (4.6) | 0.00058 |
| Spike | |||
| Median [IQR] BAU/mL | 2359 [1399, 2359] | 2110 [1227, 2359] | 0.075 |
| n (%) Positive | 215 (100) | 686 (99.4) | 0.58 |
| RBD | |||
| Median [IQR] BAU/mL | 2048 [966, 4193] | 1788 [810, 4034] | 0.19 |
| n (%) Positive | 215 (100) | 682 (98.8) | 0.21 |
| Spike AND RBD positiveb | 215 (100) | 682 (98.8) | 0.21 |
| 48 Weeks Post 2nd Dose | |||
| n (%) with a result | 200 (58.1) | 677 (78.6) | <0.0001 |
| NP | |||
| Median [IQR] BAU/mL | 7.07 [3.28, 30.25] | 3.57 [2.30, 7.75] | <0.0001 |
| n (%) Positive | 47 (23.5) | 80 (11.8) | <0.0001 |
| Spike | |||
| Median [IQR] BAU/mL | 1450 [598, 2359] | 2359 [1162, 2359] | <0.0001 |
| n (%) Positive | 200 (100) | 674 (99.6) | 0.99 |
| RBD | |||
| Median [IQR] BAU/mL | 1211 [461, 3917] | 2705 [785, 6464] | <0.0001 |
| n(%) Positive | 200 (100) | 667 (98.5) | 0.13 |
| Spike AND RBD positiveb | 200 (100) | 667 (98.5) | 0.13 |
IQR, interquartile range; RBD, receptor-binding domain; BAU, binding antibody units; NP, nucleocapsid protein.
a
p values are from Kruskal-Wallis tests for median BAU/mL values and Fisher’s Exact tests for n(%) Positive values.
b
Overall seropositivity is defined as antibody positive to both spike and RBD.