The HPV 9-valent vaccine cannot be given after the age of 30 because it can only be used for women between the ages of 16 and 26, and it is not suitable for women over the age of 30 to receive this vaccine. In addition, the nine-valent HPV vaccine can also prevent low-risk HPV type 6 and 11 infections, which can prevent vulvar condyloma, and cervical pre-cancer screening is required routinely after HPV vaccination.