Table 3.
Antibody responses at 14 and 28 days post-administration of the second vaccine dose.
| 14 days post the second vaccination | 28 days post the second vaccination | |||||
| Items | 5 μg group | 10 μg group | Placebo group | 5 μg group | 10 μg group | Placebo group |
| Phase 1 trial (0/14) | ||||||
| N | 23 | 24 | 12 | 23 | 24 | 12 |
| Neutralising antibody to live SARS-CoV-2 | ||||||
| Seroconversion | 23 (100.0, 85.2–100.0) | 23 (95.8, 78.9–100.0) | 0 | 23 (100.0, 85.2–100.0) | 24 (100.0, 85.8–100.0) | 0 |
| GMT | 30.9 (20.6–46.4) | 40.6 (23.0–71.8) | 2.0 (2.0–2.0) | 29.3 (19.6–43.8) | 49.1 (33.5–72.0) | 2.0 (2.0–2.0) |
| Neutralising antibody to pseudovirus | ||||||
| Seroconversion | 22 (95.7, 78.1–99.9) | 21 (87.5, 67.6–97.3) | 0 | 22 (95.7, 78.1–99.9) | 21 (87.5, 67.6–97.3) | 0 |
| GMT | 90.4 (67.3–121.5) | 116.7 (71.1–191.6) | 7.8 (5.5–11.1) | 69.4 (53.8–89.6) | 99.8 (61.7–161.4) | 7.9 (5.4–11.4) |
| RBD-IgG | ||||||
| Seroconversion | 23 (100.0, 85.2–100.0) | 24 (100.0, 85.8–100.0) | 0 | 23 (100.0, 85.2–100.0) | 24 (100.0, 85.8–100.0) | 0 |
| GMT | 616.0 (381.9–993.7) | 1169.8 (694.2–1971.1) | 10.0 (10.0–10.0) | 605.3 (436.4–839.7) | 962.0 (613.5–1508.6) | 10.0 (10.0–10.0) |
| Phase 2 trial (0/14) | ||||||
| N | 100 | 98 | 48 | 100 | 97 | 48 |
| Neutralising antibody to live SARS-CoV-2 | ||||||
| Seroconversion | 96 (96.0, 90.1–98.9) | 95 (96.9, 91.3–99.4) | 0 | 98 (98.0, 93.0–99.8) | 96 (99.0, 94.4–99.8) | 0 |
| GMT | 41.5 (32.8–52.5) | 48.3 (37.5–62.1) | 2.0 (2.0–2.0) | 37.2 (29.5–46.9) | 44.5 (35.5–55.7) | 2.0 (2.0–2.0) |
| Neutralising antibody to pseudovirus | ||||||
| Seroconversion | 87 (87.0, 78.8–92.9) | 90 (91.8, 84.6–96.4) | 0 | 83 (83.0, 74.2–89.8) | 88 (90.7, 83.1–95.7) | 0 |
| GMT | 94.4 (78.0–114.3) | 118.7 (96.4–146.2) | 7.7 (6.5–9.1) | 74.4 (62.6–88.5) | 97.6 (79.7–119.4) | 8.9 (7.5–10.6) |
| RBD-IgG | ||||||
| Seroconversion | 97 (97.0, 91.5–99.4) | 95 (96.9, 91.3–99.4) | 2 (4.2, 0.5–14.3) | 98 (98.0, 93.0–99.8) | 97 (100.0, 96.3–100.0) | 1 (2.1, 0.1–11.1) |
| GMT | 636.9 (496.5–816.7) | 652.7 (519.2–820.6) | 11.1 (9.4–13.0) | 623.0 (511.7–758.6) | 686.4 (574.2–820.1) | 10.5 (9.5–11.5) |
| Phase 2 trial (0/28) | ||||||
| N | 100 | 99 | 49 | 98 | 99 | 49 |
| Neutralising antibody to live SARS-CoV-2 | ||||||
| Seroconversion | 98 (98.0, 93.0–99.8) | 99 (100.0, 96.3–100.0) | 0 | 97 (99.0, 94.5–100.0) | 99 (100.0, 96.3–100.0) | 0 |
| GMT | 110.5 (92.4–132.2) | 100.2 (84.6–118.7) | 2.0 (2.0–2.0) | 131.7 (109.3–158.6) | 110.7 (94.7–129.4) | 2.0 (2.0–2.0) |
| Neutralising antibody to pseudovirus | ||||||
| Seroconversion | 99 (99.0, 94.6–100.0) | 98 (99.0, 94.5–100.0) | 0 | 95 (96.9, 91.3–99.4) | 96 (97.0, 91.4–99.4) | 1 (2.0, 0.1–10.9) |
| GMT | 276.6 (236.2–323.9) | 240.1 (204.3–282.2) | 8.1 (6.9–9.6) | 167.4 (142.6–196.5) | 153.6 (131.2–179.8) | 8.6 (7.2–10.2) |
| RBD-IgG | ||||||
| Seroconversion | 98 (98.0, 93.0–100.0) | 98 (99.0, 94.5–100.0) | 0 | 96 (98.0, 92.8–99.8) | 99 (100.0, 96.3–100.0) | 0 |
| GMT | 2485.5 (2051.2–3011.9) | 2037.3 (1643.4–2525.5) | 10.2 (9.8–10.6) | 1594.0 (1334.4–1904.1) | 1496.8 (1255.9–1783.9) | 10.3 (9.7–10.8) |
Data are n (95% CI) for GMT, number of participants (%, 95% CI [%]) for seroconversion. 0/14 or 0/28: Participants received two doses on Days 0 and 14 or Days 0 and 28, respectively; CI: Confidence interval; GMT, geometric mean titer; N: Number of participants included in each treatment group for the per-protocol immunogenicity analysis; RBD-IgG: Antibody directed against the receptor-binding domain; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2.