Table 2.
Cellular immunogenicity outcomes against wild type SARS-CoV-2 S, N and M peptide pools post-dose 2 and post-dose 3 of CoronaVac in the evaluable analysis population
| Variables | Intramuscular | Intradermal | ||
|---|---|---|---|---|
| 2 doses | 3 doses | 2 doses | 3 doses | |
| Total SNM-specific T-cell responses on flow cytometry | ||||
| n | 60 | 58 | 48 | 40 |
| GM% IFN-γ+CD4+ T cells (95% CI) | 0.058 (0.040–0.083) | 0.066 (0.041–0.106) | 0.107 (0.063–0.183) | 0.102 (0.053–0.197) |
| %positive (≥ cut-off at 0.0075%) | 83.3 | 74.1 | 81.3, P = 0.804 | 77.5, P = 0.813 |
| GM% IL-2+CD4+ T cells (95% CI) | 0.040 (0.030–0.052) | 0.073 (0.049–0.109) | 0.112 (0.068–0.183) | 0.143 (0.077–0.264) |
| %positive (≥ cut-off at 0.0075%) | 83.3 | 79.3 | 79.2, P = 0.624 | 80.0, P > 0.9999 |
| GM% IFN-γ+CD8+ T cells (95% CI) | 0.050 (0.033–0.077) | 0.071 (0.040–0.125) | 0.059 (0.033–0.104) | 0.062 (0.032–0.123) |
| %positive (≥ cut-off at 0.0075%) | 65.0 | 62.1 | 62.5, P = 0.842 | 62.5, P > 0.9999 |
| GM% IL-2+CD8+ T cells (95% CI) | 0.017 (0.014–0.022) | 0.041 (0.027–0.063) | 0.050 (0.031–0.080) | 0.066 (0.034–0.128) |
| %positive (≥ cut-off at 0.0075%) | 58.3 | 65.5 | 68.8, P = 0.318 | 65.0, P > 0.9999 |
| S-specific T-cell responses on flow cytometry | ||||
| n | 60 | 59 | 48 | 41 |
| GM% IFN-γ+CD4+ T cells (95% CI) | 0.023 (0.015–0.036) | 0.016 (0.010–0.027) | 0.022 (0.012–0.040) | 0.025 (0.013–0.048) |
| %positive (≥ cut-off at 0.005%) | 70.0 | 57.6 | 58.3, P = 0.229 | 68.3, P = 0.303 |
| GM% IL-2+CD4+ T cells (95% CI) | 0.015 (0.011–0.020) | 0.017 (0.010–0.027) | 0.020 (0.012–0.035) | 0.031 (0.017–0.059) |
| %positive (≥ cut-off at 0.005%) | 73.3 | 61.0 | 60.4, P = 0.214 | 68.3 P = 0.528 |
| GM% IFN-γ+CD8+ T cells (95% CI) | 0.014 (0.009–0.024) | 0.017 (0.010–0.031) | 0.014 (0.008–0.025) | 0.010 (0.005–0.019) |
| %positive (≥ cut-off at 0.005%) | 48.3 | 49.2 | 45.8, P = 0.848 | 39.0, P = 0.414 |
| GM% IL-2+CD8+ T cells (95% CI) | 0.006 (0.005–0.008) | 0.009 (0.006–0.015) | 0.012 (0.007–0.020) | 0.010 (0.005–0.018) |
| %positive (≥ cut-off at 0.005%) | 48.3 | 47.5 | 52.1, P = 0.847 | 41.5%, P = 0.683 |
| N-specific T-cell responses on flow cytometry | ||||
| n | 60 | 58 | 48 | 40 |
| GM% IFN-γ+CD4+ T cells (95% CI) | 0.011 (0.008–0.017) | 0.014 (0.008–0.024) | 0.022 (0.011–0.043) | 0.023 (0.012–0.047) |
| %positive (≥ cut-off at 0.005%) | 55.0 | 53.5 | 54.2, P > 0.9999 | 60.0, P = 0.542 |
| GM% IL-2+CD4+ T cells (95% CI) | 0.013 (0.009–0.018) | 0.020 (0.012–0.033) | 0.028 (0.015–0.053) | 0.030 (0.015–0.059) |
| %positive (≥ cut-off at 0.005%) | 66.7 | 60.3 | 60.4, P = 0.549 | 65.0, P = 0.677 |
| GM% IFN-γ+CD8+ T cells (95% CI) | 0.008 (0.005–0.012) | 0.015 (0.008–0.028) | 0.016 (0.008–0.031) | 0.013 (0.006–0.026) |
| %positive (≥ cut-off at 0.005%) | 31.7 | 41.4 | 43.8, P = 0.232 | 40.0, P > 0.9999 |
| GM% IL-2+CD8+ T cells (95% CI) | 0.0042 (0.003–0.005) | 0.010 (0.006–0.016) | 0.014 (0.008–0.024) | 0.014 (0.007–0.027) |
| %positive (≥ cut-off at 0.005%) | 28.3 | 41.4 | 47.9, P = 0.046 | 50.0, P = 0.417 |
| M-specific T-cell responses on flow cytometry | ||||
| n | 60 | 59 | 48 | 40 |
| GM% IFN-γ+CD4+ T cells (95% CI) | 0.007 (0.005–0.010) | 0.006 (0.004–0.009) | 0.008 (0.005–0.014) | 0.010 (0.005–0.020) |
| %positive (≥ cut-off at 0.005%) | 36.7 | 23.7 | 35.4, P > 0.9999 | 32.5, P = 0.365 |
| GM% IL-2+CD4+ T cells (95% CI) | 0.006 (0.004–0.007) | 0.006 (0.004–0.009) | 0.011 (0.006–0.019) | 0.014 (0.006–0.029) |
| %positive (≥ cut-off at 0.005%) | 46.7 | 25.4 | 41.7, P = 0.698 | 45.0, P = 0.052 |
| GM% IFN-γ+CD8+ T cells (95% CI) | 0.006 (0.004–0.009) | 0.005 (0.003–0.008) | 0.007 (0.004–0.011) | 0.012 (0.006–0.0242) |
| %positive (≥ cut-off at 0.005%) | 25.0 | 13.6 | 29.2, P = 0.667 | 42.5, P = 0.002 |
| GM% IL-2+CD8+ T cells (95% CI) | 0.004 (0.003–0.005) | 0.004 (0.003–0.006) | 0.005 (0.003–0.008) | 0.012 (0.006–0.024) |
| %positive (≥ cut-off at 0.005%) | 23.3 | 18.6 | 27.1, P = 0.662 | 47.5, P = 0.004 |
SARS-CoV-2 severe acute respiratory syndrome coronavirus 2, S spike protein, N nucleocapsid protein, M membrane protein, SNM sum of individual S, N, and M peptide pools, GM geometric mean, CI confidence interval, IFN-γ interferon-gamma, IL-2 interleukin-2. P values compare the proportion of positive responses between intramuscular and intradermal administration by Fisher’s exact test