Table 2.
Antibody response to spike and neutralizing antibodies to live SARS-CoV-2 at baseline and post-vaccination
| Anti-S ELISA (AU/mL) |
SARS-CoV-2 neutralization (NT50) |
SARS-CoV-2 neutralization (NT80) |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Visit (day) | Statistic | SD (N = 298) | RD (N = 300) | PL (N =3 01) | SD (N = 298) | RD (N = 300) | PL (N = 301) | SD (N = 298) | RD (N = 300) | PL (N = 301) |
| 1 | n | 298 | 300 | 301 | 298 | 297 | 300 | 298 | 299 | 301 |
| GM | 1.73 | 1.77 | 1.71 | 5.35 | 5.35 | 5.31 | 4.15 | 4.16 | 4.11 | |
| 95% CI for GM | 1.66,1.80 | 1.68,1.87 | 1.64,1.78 | 4.99,5.74 | 5.01,5.72 | 4.98,5.67 | 4.02,4.28 | 4.05,4.27 | 4.01,4.21 | |
| 22 | n | 291 | 295 | 288 | 291 | 294 | 288 | 291 | 295 | 288 |
| GM | 40.54 | 41.13 | 1.71 | 45.29 | 47.34 | 4.91 | 14.70 | 15.09 | 4.09 | |
| 95% CI for GM | 35.62,46.14 | 36.25,46.67 | 1.64,1.79 | 38.83,52.82 | 40.50,55.35 | 4.63,5.20 | 12.84,16.82 | 13.07,17.41 | 3.99,4.20 | |
| GMFR | 23.63 | 23.17 | 1.01 | 8.64 | 8.84 | 0.95 | 3.58 | 3.63 | 1.00 | |
| seroresponse (%) | 93.5 | 92.5 | 0 | 73.2 | 74.8 | 0 | 46.7 | 43.1 | 0 | |
| 36 | n | 287 | 293 | 279 | 286 | 292 | 278 | 287 | 292 | 278 |
| GM | 45.15 | 77.94 | 1.73 | 47.88 | 86.11 | 5.09 | 17.31 | 29.91 | 4.12 | |
| 95% CI for GM | 39.54,51.56 | 70.36,86.33 | 1.65,1.81 | 41.22,55.60 | 75.43,98.30 | 4.77,5.43 | 15.18,19.73 | 26.31,34.01 | 4.02,4.23 | |
| GMFR | 26.29 | 43.87 | 1.02 | 9.09 | 16.08 | 0.98 | 4.21 | 7.21 | 1.01 | |
| seroresponse (%) | 92 | 99.3 | 0 | 76.2 | 90.1 | 0.4 | 53 | 76 | 0 | |
| 57 | n | 279 | 288 | 232 | 279 | 288 | 232 | 279 | 288 | 232 |
| GM | 35.88 | 55.74 | 1.80 | 48.36 | 80.91 | 5.08 | 19.31 | 30.37 | 4.19 | |
| 95% CI for GM | 31.23,41.22 | 50.11,62.01 | 1.68,1.94 | 40.75,57.38 | 70.19,93.26 | 4.71,5.48 | 16.66,22.39 | 26.48,34.84 | 4.02,4.37 | |
| GMFR | 20.85 | 31.32 | 1.07 | 9.17 | 15.13 | 0.99 | 4.69 | 7.28 | 1.02 | |
| seroresponse (%) | 90.3 | 97.9 | 1.3 | 72 | 87.5 | 1.7 | 54.8 | 75.7 | 0.9 | |
| 180 | n | 193 | 238 | – | 194 | 235 | – | 194 | 235 | – |
| GM | 13.40 | 15.50 | – | 26.94 | 31.51 | – | 11.67 | 12.95 | – | |
| 95% CI for GM | 11.45,15.68 | 13.56,17.73 | – | 22.16,32.75 | 26.50,37.48 | – | 9.87,13.80 | 11.17,15.02 | – | |
| GMFR | 7.75 | 8.70 | – | 5.02 | 5.85 | – | 2.83 | 3.10 | – | |
| seroresponse (%) | 74.6 | 82.4 | – | 59.8 | 62.6 | – | 35.6 | 39.6 | – | |
The 95% CIs were calculated based on the t-distribution of the natural log-transformed values, which were then back transformed to the original scale. Data from LABCORP and VIROCLINICS-DDL Central Laboratory. Seroresponse is defined as ≥4-fold rise in titers post-baseline. N, number of volunteers in the IAS population; n, number of volunteers in the IAS population with available data at each time point; GM, geometric mean; GMFR, GM fold rise; SD, single dose; RD, repeated dose; PL, placebo.