The Base Study V501-041 duration was 30 months. The study was extended to further evaluate the efficacy of Quadrivalent HPV (Type 6, 11, 16, 18) L1 VLP (qHPV) vaccine against Cervical Intraepithelial Neoplasia Grade 2 (CIN 2), CIN 3, Adenocarcinoma In Situ (AIS), and/or cervical cancer. The efficacy was followed through the Month 78 visit, and the close-out visit was conducted at approximately Month 90 with only safety data collected