Cervical cancer is second only to breast cancer in the incidence of female malignancies, and most of cervical cancer is caused by HPV infection. Cervical cancer vaccine (HPV vaccine) is mainly to protect against HPV infection. After cervical cancer vaccination, there is no guarantee that cervical cancer will not be prevented, which is mainly related to the following factors: 1. Types of HPV: There are many types of HPV viruses, and more than 120 subtypes are known, among which 10 are closely related to the development of cervical cancer, with HPV type 16 and 18 as the most important high-risk types. Among the currently available preventive vaccines, different valence types can prevent infection of different subtypes of HPV viruses; 2. The bivalent vaccine mainly prevents high-risk HPV types HPV16 and HPV18. The quadrivalent vaccine mainly prevents HPV infections of HPV16, HPV18, HPV6 and HPV11. The nine-valent vaccine can prevent most of the high-risk HPV types that cause cervical cancer, and has a high success rate. In general, after vaccination, it can only prevent cervical cancer caused by specific subtypes of HPV virus to a certain extent, and cannot achieve complete blockage; 3. Personal factors: The immunity of HPV vaccine is linked to age, and usually the earlier the injection time, the better the effect. In addition, long-term unclean sexual life, as well as suffering from chronic inflammatory diseases and immune deficiency can also affect the immunization effect of HPV vaccine.