Table 3.
Immunogenicity against prototype SARS-CoV in adolescents with and without (Naïve) serologic evidence of prior exposure to COVID-19 before vaccination as geometric mean titers (GMT), seroconversion rate (SCR) and geometric mean-fold rise (GMFR).
| Pre-exposed adolescents |
Naïve adolescents with SCB-2019a | |||
|---|---|---|---|---|
| SCB-2019 | Placebo | |||
| Neutralizing antibodies (IU/mL)b | ||||
| Day 1 (Baseline) | N = | 149 | 14 | 55 |
|
GMT 95% CI) |
173 (135, 222) |
244 (106, 559) |
13.7 (11.4, 16.6) |
|
| Day 22 | N = | 148 | 15 | 56 |
|
GMT (95% CI) |
702 (619, 796) |
225 (114, 443) |
15.6 (12.6, 19.3) |
|
|
SCR, n [%] (95% CI) |
71 [48] (39.7, 56.3) |
1 [7] (0.2, 33.9) |
1 [2] (0, 9.7) |
|
| GMFR (95% CI) | 4.0 (3.2, 5.0) | 1.0 (0.6, 1.7) | 1.1 (1.0, 1.3) | |
| Day 36 | N = | 149 | 15 | 55 |
|
GMT (95% CI) |
982 (881, 1094) |
166 (82.9, 333) |
271 (211, 348) |
|
|
SCR, n [%] (95% CI) |
90 [60] (52.1, 68.3) |
1 [7] (0.2, 33.9) |
47 [86] (73, 94) |
|
| GMFR (95% CI) | 5.7 (4.5, 7.1) | 0.7 (0.4, 1.2) | 19.8 (15.0, 26.1) | |
| SCB-2019 binding antibodies (IU/mL)c | ||||
| Day 1 (Baseline) | N = | 149 | 14 | 55 |
|
GMT (95% CI) |
5.7 (4.5, 7.2) |
7.5 (3.8, 14.8) |
0.5 (0.5, 0.6) |
|
| Day 22 | N = | 147 | 15 | 56 |
|
GMT (95% CI) |
27.4 (23.3, 32.3) |
5.8 (3.2, 10.5) |
0.9 (0.7, 1.1) |
|
|
SCR, n [%] (95% CI) |
72 [49] (40.7, 57.3) |
1 [7] (0.2, 33.9) |
3 [6] (1.1, 15.1) |
|
| GMFR (95% CI) | 4.7 (3.6, 6.1) | 0.8 (0.5, 1.3) | 1.7 (1.3, 2.1) | |
| Day 36 | N = | 149 | 15 | 55 |
|
GMT (95% CI) |
31.3 (26.4, 37.0) |
4.1 (2.7, 6.4) |
14 (110, 17.8) |
|
|
SCR, n [%] (95% CI) |
84 [56] (48.0, 64.5) |
1 [7] (0.2, 33.9) |
52 [95] (84.9, 98.9) |
|
| GMFR (95% CI) | 5.5 (4.3, 7.2) | 0.6 (0.3, 0.9) | 26.5 (20.2, 34.7) | |
aNaïve adolescents had no evidence of prior exposure to SARS-CoV-2 or COVID-19.
bconverted to International Units per mL (IU/mL) with the WHO international standard.
cSCB-2019 binding antibodies against prototype SARS-CoV-2 virus determined by ELISA (IU/mL).