Table 2.
Vaccine effectiveness among children and adolescents with different vaccination status.
| Vaccination status | Case | Control | Crude OR (95% CI) | Adjusted OR (95% CI) | VE% (95% CI) |
|---|---|---|---|---|---|
| COVID-19 | |||||
| Unvaccinated | 17,825 | 48,738 | (Ref) | (Ref) | (Ref) |
| 1 dose | |||||
| BNT162b2 | 4100 | 13,241 | 0.733 (0.700–0.769) | 0.721 (0.688–0.756) | 27.9 (24.4; 31.2) |
| CoronaVac | 6011 | 20,016 | 0.800 (0.772–0.828) | 0.793 (0.766–0.821) | 20.7 (17.9; 23.4) |
| 2 doses | |||||
| All BNT162b2 | 5401 | 17,121 | 0.704 (0.670–0.741) | 0.687 (0.653–0.722) | 31.3 (27.8; 34.7) |
| All CoronaVac | 2522 | 7595 | 0.793 (0.748–0.842) | 0.783 (0.738–0.830) | 21.7 (17.0; 26.2) |
| 3 doses | |||||
| All BNT162b2 | 389 | 1660 | 0.449 (0.392–0.514) | 0.440 (0.384–0.504) | 56.0 (49.6; 61.6) |
| All CoronaVac | 130 | 463 | 0.619 (0.505–0.759) | 0.606 (0.494–0.744) | 39.4 (25.6; 50.6) |
| B-B-C | 55 | 161 | 0.674 (0.492–0.922) | 0.656 (0.480–0.899) | 34.4 (10.1; 52.0) |
| C-C-B | 1 | 9 | 0.229 (0.029–1.814) | 0.225 (0.028–1.783) | 77.5 (−78.3; 97.2) |
| COVID-19-related hospitalization | |||||
| Unvaccinated | 1188 | 11,181 | (Ref) | (Ref) | (Ref) |
| 1 dose | |||||
| BNT162b2 | 157 | 1631 | 0.758 (0.619–0.928) | 0.796 (0.650–0.975) | 20.4 (2.5; 35.0) |
| CoronaVac | 290 | 2993 | 0.902 (0.781–1.042) | 0.919 (0.795–1.062) | 8.1 (−6.2; 20.5) |
| 2 doses | |||||
| All BNT162b2 | 202 | 2494 | 0.588 (0.480–0.720) | 0.624 (0.509–0.766) | 37.6 (23.4; 49.1) |
| All CoronaVac | 343 | 2753 | 1.147 (0.975–1.348) | 1.175 (0.998–1.383) | −17.5 (−38.3; 0.2) |
| 3 doses | |||||
| All BNT162b2 | 29 | 478 | 0.385 (0.248–0.599) | 0.411 (0.264–0.639) | 58.9 (36.1; 73.6) |
| All CoronaVac | 12 | 213 | 0.477 (0.261–0.872) | 0.483 (0.264–0.884) | 51.7 (11.6; 73.6) |
| B-B-C | 10 | 43 | 1.511 (0.727–3.140) | 1.563 (0.751–3.250) | −56.3 (−225.0; 24.9) |
| C-C-B | 0 | 2 | – | – | – |
| Severe COVID-19 | |||||
| Unvaccinated | 1044 | 9956 | (Ref) | (Ref) | (Ref) |
| 1 dose | |||||
| BNT162b2 | 128 | 1307 | 0.780 (0.623–0.976) | 0.809 (0.646–1.013) | 19.1 (−1.3; 35.4) |
| CoronaVac | 247 | 2596 | 0.897 (0.767–1.049) | 0.912 (0.779–1.068) | 8.8 (−6.8; 22.1) |
| 2 doses | |||||
| All BNT162b2 | 165 | 2079 | 0.586 (0.469–0.732) | 0.609 (0.488–0.762) | 39.1 (23.8; 51.2) |
| All CoronaVac | 294 | 2306 | 1.231 (1.029–1.474) | 1.249 (1.042–1.497) | −24.9 (−49.7; −4.2) |
| 3 doses | |||||
| All BNT162b2 | 22 | 360 | 0.379 (0.228–0.631) | 0.398 (0.239–0.663) | 60.2 (33.7; 76.1) |
| All CoronaVac | 12 | 182 | 0.584 (0.318–1.072) | 0.578 (0.314–1.062) | 42.2 (−6.2; 68.6) |
| B-B-C | 6 | 35 | 1.107 (0.444–2.764) | 1.120 (0.448–2.799) | −12.0 (−179.9; 55.2) |
| C-C-B | 0 | 2 | – | – | – |
OR: odds ratio, VE: vaccine effectiveness, CI: confidence interval, B-B-C: two doses of BNT162b2 followed by CoronaVac, C-C-B: two doses of CoronaVac followed by BNT162b2.