Table 2.
Geometric mean titre (GMT) of anti-spike antibody in SARS-CoV-2 naive, breakthrough infection and individuals with past history of COVID-19 after first dose of vaccine until 6-month after the second dose.
| Antibody titer, Geometric Mean (95% CI) in AU/mL |
|||||
|---|---|---|---|---|---|
| First sample, |
Second sample, |
Third sample, |
Fourth sample, |
P∗∗ | |
| 21 days post-V1 | 21 days post-V2 | 3-months post-V2 | 6-months post-V2 | ||
| Total cohort;N = 481 | 97.72 | 117.18 | 100 | 69.18 | P < 0.001; d - <0.001, e − <0.001, f - <0.001, g - 0.005, h - <0.001, i -<0.001 |
| (96.45–97.87) | (116.54–117.65) | (98.94–100.52) | (68.95–69.33) | ||
| SARS-CoV-2 naïve;N = 360 | 40.22 | 102.98 | 67.83 | 44.77 | P < 0.001; d - <0.001, e − <0.001, f - 0.177, g - <0.001, h - <0.001, i - <0.001 |
| (39.62–40.89) | (101.59–103.22) | (67.24–68.15) | (44.09–45.23) | ||
| Breakthrough infection; N = 64 | 37.15 | 93.32 | 338.84 | 245.47 | P < 0.001; d - <0.001, e − <0.001, f - <0.001, g - <0.001, h - <0.001, i - <0.001 |
| (37.03, 37.26) | (93.21–93.46) | (337.77–339.16) | (245.29–245.54) | ||
| Past history of COVID-19; N = 57 | 240.28 | 303.71 | 277.86 | 205.24 | P < 0.001; d - 0.049, e − 0.262, f - 0.146, g - 0.149, h - <0.001, i - <0.001 |
| (238.76–240.01) | (302.94–304.02) | (276.19–278.22) | (204.87–206.31) | ||
| p∗ | p < 0.001; a - <0.001,b - 0.370, c - <0.001 | p < 0.001; a - <0.001,b - 0.684, c - <0.001 | p < 0.001; a - <0.001,b - <0.001; c - 0.397 | p < 0.001; a - <0.001,b - <0.001; c - 0.369 | |
| SARS-CoV-2 naive cohorts, N = 360 | |||||
| Covishield recipients | 61.93 | 132.88 | 112.78 | 73.83 | P < 0.001; d - <0.001, e − <0.001, f - 0.012, g - <0.001, h - <0.001, i - <0.001 |
| (54.85–69.52) | (122.88–144.40) | (100.23–126.89) | (64.54–84.47) | ||
| Covaxin recipients | 16.17 | 50.11 | 50.81 | 46.27 | P < 0.001; d - <0.001, e − <0.001, f - 0.002, g −0.201, h - 0.891, i - 0.634 |
| (10.96–23.87) | (37.30–67.31) | (33.46–77.15) | (31.18–68.68) | ||
| p∗ | <0.001 | <0.001 | <0.001 | 0.010 | |
| Propensity-matched SARS-CoV-2 naive cohorts, N = 41 | |||||
| Covishield recipients | 56.93 | 128.94 | 111.83 | 71.28 | P < 0.001; d - <0.001, e − <0.001, f - 0.019, g - <0.001, h - <0.001, i - <0.001 |
| (53.74–60.28) | (124.48–130.65) | (108.98–124.83) | (63.4–83.47) | ||
| Covaxin recipients | 18.72 | 53.83 | 51.31 | 47.73 | P < 0.001; d - <0.001, e − <0.001, f - 0.004, g - 0.840, h - 0.392, i- 0.296 |
| (14.68–25.11) | (39.07–66.18) | (34.96–76.74) | (34.78–69.92) | ||
| p∗ | <0.001 | <0.001 | <0.001 | 0.021 | |
p∗ < 0.05 considered as statistically significant when p computed by ANOVA test followed by post-hoc Bonferroni test; a: p value between SARS-CoV-2 naive and past history of COVID-19, b: p value between SARS-CoV-2 naive and breakthrough infection, c: p value between past history of COVID-19 and breakthrough infection; AND.
P∗∗ < 0.05 considered as statistically significant when p computed by repeated measures ANOVA followed by post-hoc test; d: p value between first and second samples, e: p value between first and third samples, f: p value between first and fourth samples, g: p value between second and third samples, h: p value between second and fourth samples, i: p value between third and fourth samples.
V1: first dose of vaccine; V2: Second dose of vaccine; CI: Confidence interval; SARS-CoV-2: Severe acute respiratory syndrome coronavirus 2; COVID-19: Coronavirus disease 2019; AU: Arbitrary unit.