Plateau Antibody Levels of a Recombinant (E.Coli) HPV Nonavalent Vaccine Versus Gardasil®9 in Young Women

• Recombinant Human Papillomavirus Nonavalent (Types 6,11,16,18,31,33,45,52,58 )Vaccine(E.Coli) (Biological): Three doses administered intramuscularly at 0, 45 day and 6 month.
• Gardasil®9 (Biological): Three doses administered intramuscularly at 0, 45 day and 6 month.

Primary outcomes

• Anti-HPV 6, 11, 16, 18, 31, 33, 45, 52, and 58 type specific neutralizing antibody level [30-36 months after the first dose]: Anti-HPV 6,11,16,18,31,33,45,52 and 58 seropositive rates and geometric mean concentrations at months 30-36

Sex: Female, ages: 20 Years to 28 Years, accepts healthy volunteers

Inclusion Criteria:

* Subject who had previously participated in the Randomized, Single-blind Study to Compare Immunogenicity of a Recombinant Human Papillomavirus Nonavalent (Types 6,11,16,18,31,33,45,52,58) Vaccine(E.Coli) (Xiamen Innovax Biotech Co.,Ltd.) Versus Gardasil®9 (Merck \& Co., Inc.) in Healthy Females 18-26 Years of Age (Protocol No.: HPV-PRO-011, Identifiers: NCT04782895), and received at least one dose ;
* Subject is able to understand and comply with the requirements of the protocol(e.g. biological specimen collection, return for follow-up visits), and written informed consent must be obtained from the subject prior to enrollment;

Exclusion Criteria:

* Subject who had used other HPV vaccine products (including marketed and unmarketed vaccines) after participating in the Randomized, Single-blind Study to Compare Immunogenicity of a Recombinant Human Papillomavirus Nonavalent (Types 6,11,16,18,31,33,45,52,58) Vaccine(E.Coli) (Xiamen Innovax Biotech Co.,Ltd.) Versus Gardasil®9 (Merck \& Co., Inc.) in Healthy Females 18-26 Years of Age (Protocol No.: HPV-PRO-011, Identifiers: NCT04782895) ;
* Subject has abnormal coagulation function (such as coagulation factor deficiency, coagulopathy, platelet abnormalities) or coagulation disorders;
* Medical, psychological, social conditions, occupation or other factors, which considered by the investigator that may influence the conduct of the clinical study.

• Results publication: Zhong GH, Bi ZF, Chu K, Zhang L, Chen L, Zhu KX, Quan JL, Nie C, Chen Q, Qiu LX, Xu JB, Li JX, Zhang ML, Liu S, Nie LL, Li K, Su YY, Huang SJ, Zhang QF, Huang WJ, Pan HX, Wu T, Zhang J, Xia NS. Immunogenicity comparison of an Escherichia coli-produced 9-valent human papillomavirus vaccine and Gardasil9 in Chinese women aged 18-26 years: three-year follow-up data from a randomised clinical trial. Lancet Reg Health West Pac. 2025 Aug 27;62:101671. doi: 10.1016/j.lanwpc.2025.101671. eCollection 2025 Sep. PMID 40919385

• Jun Zhang, master, Study chair, Xiamen University
• Feng-cai Zhu, master, Principal investigator, Jiangsu Provincial Centre for Disease Control and Prevention