HPV is not only the cause of cervical cancer, but is increasingly recognized as an important cause of some oropharyngeal, vulvar, and anal cancers(1). Given the many similarities between HPV-related cancers at the cervix and other anatomic sites, researchers are optimistic that the HPV vaccine will protect against extra-cervical infections with high vaccine efficacy. In fact, the vaccine shown to confer near complete protection against cervical, vulvar and vaginal precancers associated with HPV16 or 18. To determine whether the HPV16/18 prophylactic vaccine protects against HPV16/18 infections in the oral, vulvar, and anal regions, we propose to collect oral, vulvar, and anal specimens from women in the NCI-sponsored Costa Rican community-based randomized phase III clinical trial and to test these specimens for presence of HPV DNA. The main aim of this proof of principle study is to determine the impact of HPV vaccination in preventing infections at all of these mucosal epithelial surfaces among the ~7500 women in the on-going trial.