The vaccine protects against infection with the sexually transmitted human papillomavirus , which can cause cancers of the cervix, vulva, vagina and anus. “Increasing delivery of HPV vaccination at the recommended ages of 11 or 12 years, before most adolescents are exposed to the virus, can ensure adolescents are protected against HPV infections and associated cancers,” according to the report from the U.S. Centers for Disease Control and Prevention.