This is a phase II clinical study of the novel recombinant HPV 16/18 bivalent vaccine expressed in E. coli.

The primary purpose of this study is to evaluate which dosage of the HPV vaccine can induce higher antibody and at the same time caused less adverse events.

The secondary purpose of this study is to to evaluate the safety and immunopersistence of the study vaccine.

Totally 1600 healthy women of 18-25 years of age were enrolled. The participants were randomly stratified into 4 groups and receive different dosage of human papillomavirus (HPV) vaccine or placebo administered intramuscularly according to a 0-1-6 month schedule. The women were actively monitored for adverse events for 1 month after each injection. Severe adverse events during the trial were followed up. Serum samples from all the subjects would be collected on day 0, 7m, 24m, 48m and 72m to evaluate the immunogenicity and immuno-persistency.

Inclusion Criteria:

• Written informed consent from the subject prior to enrolment;
• Female between, and including, 18 and 25 years of age at the time of enrolment;
• Subjects must be free of obvious health problems;
• Not pregnant and having no plan for pregnancy;

Exclusion Criteria:

• Pregnant or breastfeeding or having plan for pregnancy during the whole study (Month 0-7);
• Previous vaccination against HPV;
• Having severe allergic history or other immunodeficiency;
• Chemotherapy and other immunosuppressive agents using;