Immune Persistence After the Whole Vaccination Shcedule With Recombination Quadrivalent HPV Vaccine

This study is following up on participants who previously received the quadrivalent HPV vaccine (a vaccine that protects against 4 types of human papillomavirus, which can cause cervical cancer and genital warts) in earlier clinical trials. Researchers want to see how long the immune protection lasts after completing the vaccine series. **You may be eligible if...** - You previously participated in specific HPV vaccine clinical trials (protocol 4-HPV-3001 or 4-HPV-3002) - You completed all 3 doses of the HPV quadrivalent vaccine and provided a blood sample at 7 months - You were between 9 and 17 years old (Mianyang site) or over 18 at the time of the original trial - You agree to regular follow-up visits **You may NOT be eligible if...** - You are currently enrolled in or plan to join another drug or vaccine clinical trial - You have thrombocytopenia (low platelets) or a blood clotting disorder that makes blood draws risky - Your doctor determines that a condition you have might interfere with assessing immune response Talk to your doctor to see if this trial is right for you.