What is the 9-valent HPV vaccine? The 9-valent HPV vaccine is a vaccine that prevents human papillomavirus (HPV) infection and related cancers. Compared with previous HPV vaccines, the 9-valent HPV vaccine can protect against more HPV strains, including types 6, 11, 16, 18, 31, 33, 45, 52 and 58. These strains are the main culprits responsible for HPV infection and various cancers such as cervical cancer, vaginal cancer, and anal cancer. The best time to vaccinate the 9-valent HPV vaccine is before puberty, and its preventive effect is better than that in late puberty.