To support international market access and comply with World Health Organization Prequalification requirements, this lot-to-lot consistency trial is planned for initiation. The goal of this clinical trial is to evaluate lot-to-lot immunogenicity and safety of Recombinant Human Papillomavirus 9-valent (Types 6/11/16/18/31/33/45/52/58) Vaccine (Escherichia Coli) in 18-30 years-old females in China. The main question it aims to answer is:

· Is immunogenicity consistent across three commercially produced batches of Recombinant Human Papillomavirus 9-valent (Types 6/11/16/18/31/33/45/52/58) Vaccine (Escherichia coli)? Researchers will compare the immune responses at 1 month post full vaccination to see if the lot-to-lot consistency of immunogenicity can be achieved.

Participants will:

• Visit the clinic site on Month 0, 1, 2, 6 and 7.
• Take 3 doses of investigational vaccine on Month 0, 1 and 6.
• Provide approximately 5.0 mL venous blood samples on Month 0 and Month 7.
• Keep a diary of their adverse events (AEs) within 30 days after each vaccination.
• Report serious adverse events (SAEs), adverse events of special interest (AESIs), and pregnancies occurring during the trial.

Inclusion Criteria:

• Chinese female participants aged 18 to 30 years old who can provide legal identity documentation at screening, i.e., at least 18 years of age and less than 31 years of age;
• The trial participant is able to understand trial procedures and comply with protocol requirements (including biological sample collection, completion of diary/contact cards, and attendance of scheduled follow-up visits), and voluntarily signs the informed consent form;
• The trial participant agrees to avoid pregnancy and use effective contraceptive measures from the first vaccination through 1 month after completion of full vaccination;
• No prior history of sexually transmitted diseases (including syphilis, gonorrhea, chancroid, lymphogranuloma venereum, granuloma inguinale, etc.);
• No prior history of abnormal cervical screening results or cervical intraepithelial neoplasia (CIN).

Exclusion Criteria:

• Have previously received any HPV vaccine, plan to receive any HPV vaccine not supplied in this trial during the study period, or have participated in any clinical trial related to HPV vaccines;
• Axillary temperature > 37.0°C;
• Positive urine pregnancy test, current pregnancy or breastfeeding status;
• Have received any other investigational or unlicensed products (medicines or vaccines) within 30 days prior to administration of the investigational vaccine, or plan to receive such products or enroll in another clinical trial during the study;
• Have received systemic immunosuppressants, other immunomodulatory drugs or corticosteroids for a prolonged duration (≥14 consecutive days) within 6 months before vaccination. Local treatments (e.g., ointments, eye drops, inhalants or nasal sprays) are permitted;
• Have received immunoglobulins and/or blood products within 3 months prior to vaccination, or plan to receive such products within 7 months after the first vaccination;
• Have received inactivated vaccines within 14 days or live vaccines within 21 days before vaccine administration;
• Axillary temperature > 38.0°C within 3 days prior to vaccination, or any acute disease requiring systemic antibiotic or antiviral therapy within 5 days prior to vaccination;
• Current immunocompromised status, including congenital or acquired immunodeficiency disorders, Human Immunodeficiency Virus (HIV) infection, autoimmune diseases (including asplenia or splenectomy of any cause and other autoimmune diseases deemed likely to interfere with immune response by the investigator), diseases of major organs (heart, liver, spleen, lung, kidney, etc.), malignancy, etc.;
• History of hypertension or hypotension with regular medication but unstable control; or resting brachial blood pressure readings of the trial participant showing systolic blood pressure ≥160 mmHg, diastolic blood pressure ≥100 mmHg, or systolic blood pressure <90 mmHg; or with other concomitant diseases judged unsuitable for this trial after comprehensive assessment by the investigator;
• Prior or current severe illnesses with unstable conditions that may require emergency treatment or hospitalization;
• History of severe allergies, including severe adverse reactions to previous vaccinations such as dyspnea or angioedema, or known hypersensitivity to any component of the investigational vaccine (recombinant VLP protein, sodium dihydrogen phosphate, disodium hydrogen phosphate, polysorbate, aluminium hydroxide);
• Asthma with unstable disease requiring emergency care, hospitalization, oral or intravenous corticosteroid administration in the past two years;
• Prior or current coagulation dysfunction or coagulation disorders;
• Epilepsy, excluding febrile convulsions occurring before 2 years of age, alcoholic seizures within the first 3 years of alcohol withdrawal, or simple epilepsy that has required no treatment for the past 3 years;
• Participants judged by the investigator, after medical history inquiry and relevant physical examination, to have medical, psychological, social, occupational or other conditions that may interfere with the conduct of the clinical trial.