Table 3.

Analysis of efficacy against HPV 6/11/16/18–related high-grade cervical lesions (CIN 2 or worse) by categories of baseline covariates

Per-protocol populationIntention-to-treat population
Quadrivalent HPV vaccinePlaceboEfficacy, % (95% CI)Quadrivalent HPV vaccinePlaceboReduction, % (95% CI)
Cases/nRateCases/nRateCases/nRateCases/nRate
No. of sexual partners
    00/4640.08/5080.5100.0 (35.9-100.0)1/5000.18/5400.486.5 (<0.0-99.7)
    1-22/4,5020.059/4,5090.496.6 (87.3-99.6)58/4,9970.3127/5,0400.754.4 (37.3-65.1)
    ≥30/2,8980.043/2,8450.5100.0 (91.2-100.0)83/3,3210.7158/3,2741.448.1 (31.8-60.7)
    Covariate by efficacy interactionP = 0.571P = 0.395
Age at start of vaccination (y)
    ≤170/1,0390.022/1,0570.7100.0 (81.6-100.0)11/1,1260.336/1,1500.969.0 (37.8-85.8)
    18-200/3,2580.056/3,3130.6100.0 (93.1-100.0)57/3,6900.5151/3,7491.261.9 (47.9-72.4)
    ≥210/3,5670.032/3,4950.393.9 (76.1-99.3)74/4,0070.5106/3,9610.831.1 (6.4-49.5)
    Covariate by efficacy interactionP = 0.131P = 0.009
History of or day 1 abnormal Pap
    Normal2/6,7370.091/6,7390.597.8 (91.9-99.7)58/7,4620.2188/7,4880.769.2 (58.4-77.4)
    Abnormal0/8150.015/7840.7100.0 (73.9-100.0)78/9912.692/9653.218.7 (<0.0-40.7)
    Covariate by efficacy interactionP = 1.00P < 0.001
Smoking history
    Without smoking history0/2,6000.042/2,7000.5100.0 (90.5-100.0)72/5,8650.4164/5,7561.257.0 (43.0-67.9)
    With smoking history2/5,2630.068/5,1630.597.1 (89.2-99.7)70/2,9520.7129/3,0990.843.4 (23.7-58.3)
    Covariate by efficacy interactionP = 0.534P = 0.183
Hormonal contraception use
    No hormonal contraception at day 11/4,6610.069/4,6520.598.6 (91.7-100.0)41/3,5750.6107/3,6251.061.3 (44.1-73.7)
    Hormonal contraception at day 11/3,1930.041/3,1960.497.6 (85.6-99.9)101/5,2300.3186/5,2110.946.1 (31.0-58.1)
    Covariate by efficacy interactionP = 1.000P = 0.160

NOTE: n is the number of subjects evaluable (i.e., number of subjects in the given population who also have at least one follow-up visit). “Rate” is the rate per 100 person-years at risk.