Estimated Tdap VE and Duration of Protection Against Pertussis Among Adolescents Who Received All Acellular Vaccines (Birth Years 1998–2000)
| Cases (n = 450) | Controls (n = 1246) | Odds Ratio (95% CI) | Estimated VE (95% CI), % | |
|---|---|---|---|---|
| No Tdap | 109 | 154 | Reference | Reference |
| Tdap | 341 | 1092 | 0.36 (0.26 to 0.50) | 63.9 (49.7 to 74.1) |
| Time since Tdap dose | ||||
| No Tdap | 109 | 154 | Reference | Reference |
| <12 months | 69 | 332 | 0.27 (0.18 to 0.40) | 73.1 (60.3 to 81.8) |
| 12–23 months | 124 | 389 | 0.45 (0.30 to 0.68) | 54.9 (32.4 to 70.0) |
| 24–47 months | 148 | 371 | 0.66 (0.42 to 1.03) | 34.2 (−0.03 to 58.0) |