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

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.