Geometric mean ratios of neutralising, anti-receptor-binding domain, and anti-spike glycoprotein antibodies at different time points in phase I
| Antibody | Stage I (18–50 years) | Stage II (51–75 years) | |
| Geometric mean ratio* (95% CI) | Geometric mean ratio (95% CI) | ||
| 3 µg | 5 µg | 5 µg | |
| Neutralising antibody | |||
| Day 0 | 1.13 (0.72 to 1.77) | 0.87 (0.4 to 1.89) | 0.65 (0.41 to 1.04) |
| Day 14 | 1.04 (0.28 to 3.8) | 1.17 (0.38 to 3.61) | 2.93 (0.78 to 10.97) |
| Day 21 | 4.77 (1.4 to 16.33) | 5.94 (1.57 to 22.51) | 6.70 (2.05 to 21.94) |
| Day 28 | 2.86 (0.62 to 13.24) | 5.58 (1.47 to 21.14) | 14.81 (5.11 to 42.93) |
| Anti-receptor binding domain IgG | |||
| Day 0 | 1.93 (0.63 to 5.93) | 1.69 (0.66 to 4.35) | 1.40 (0.74 to 2.65) |
| Day 14 | 3.71 (0.89 to 15.37) | 22.39 (8.4 to 59.69) | 3.03 (0.84 to 10.86) |
| Day 21 | 5.99 (1.4 to 25.62) | 53.14 (25.4 to 111.19) | 39.98 (11.05 to 144.58) |
| Day 28 | 10.34 (2.65 to 40.27) | 63.7 (37.86 to 107.19) | 60.23 (21.83 to 166.16) |
| Anti-spike glycoprotein IgG | |||
| Day 0 | 7.91 (1.31 to 47.66) | 2.37 (0.61 to 9.18) | 1.23 (0.29 to 5.18) |
| Day 14 | 11.71 (1.38 to 99.25) | 11.83 (2.21 to 63.39) | 3.69 (0.63 to 21.75) |
| Day 21 | 14.92 (3.37 to 65.95) | 80.32 (35.59 to 181.29) | 117.17 (24.04 to 571.11) |
| Day 28 | 34.28 (6.69 to 175.63) | 232.26 (127.12 to 424.36) | 292.79 (98.91 to 866.70) |
Results reported at baseline (day 0), 2 weeks after the first vaccination (day 14), and 2 weeks after the second vaccination (day 28) for 3 µg, 5 µg, and placebo groups. In stage I, one participant in the 3 µg group became RT-PCR positive for COVID-19 on day seventh after the first dose and was thus excluded from the study. In stage II, one participant in the 5 µg group was excluded from the study and did not receive any doses due to white coat syndrome. Another participant in the 5 µg group of stage II became RT-PCR positive for COVID-19 within a day after the second injection and thus was excluded from data analysis.
*Neutralising antibody is reported in µg/mL—anti-receptor binding domain IgG in RU/mL—and anti-spike glycoprotein IgG in RU/mL.
RT-PCR, reverse transcription PCR.