Studies continue to prove the HPV vaccine works extremely well, decreasing the number of HPV infections and precancers since it has been available. The HPV vaccine protects against anogenital warts and cancers caused by HPV. It protects against cancer of the vagina, vulva, penis, anus, mouth, throat, head, and neck caused by HPV. When given at the recommended ages, the HPV vaccine can prevent over 90% of these cancers from ever developing. This is an estimated 33,700 cases in the United States every year.