TABLE 3

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 Tdap109154ReferenceReference
Tdap34110920.36 (0.26 to 0.50)63.9 (49.7 to 74.1)
Time since Tdap dose
No Tdap109154ReferenceReference
 <12 months693320.27 (0.18 to 0.40)73.1 (60.3 to 81.8)
 12–23 months1243890.45 (0.30 to 0.68)54.9 (32.4 to 70.0)
 24–47 months1483710.66 (0.42 to 1.03)34.2 (−0.03 to 58.0)