The difference between Quadrivalent and Nine-Valent is the range of HPV viruses prevented, and both of them are available for ages 9-45. Quadrivalent/nine-valent refers to the human papillomavirus (HPV) vaccine, and the age of both HPV vaccines is 9-45 years old. The difference between the two is mainly the different range of viruses prevented. Quadrivalent HPV vaccine mainly prevents the viruses of four subtypes of HPV6, 11, 16 and 18; and the nine-valent HPV vaccine mainly prevents the viruses of nine subtypes of HPV6, 11, 16, 18, 31, 33, 45, 52 and 58. It should be noted that pregnant women or women preparing for pregnancy should postpone vaccination until the end of pregnancy, and breastfeeding women should be cautious when receiving the vaccine. HPV vaccination is prohibited for those who have hypersensitivity to the active ingredient of the vaccine or to any of the excipient components, and those who have symptoms of hypersensitivity after injection of the product should not be revaccinated with the product. Regular cervical cancer screening is still required after HPV vaccination.