Extended Follow Up of Young Women in Costa Rica Who Received Vaccine for Human Papillomavirus Types 16 and 18 and Unvaccinated Controls

Inclusion Criteria: * Women who participated in the Costa Rica Vaccine Trial (CVT) and lived in the Guanacaste province and a few areas of Puntarenas closest to Guanacaste will be eligible for the long-term follow up LTFU study * Women who received the HPV-16/18 vaccine at the start of CVT will be invited for up to 6 years of additional follow-up, and women who were originally in the control arm of CVT and were offered the HPV-16/18 vaccine at crossover will be invited for an additional 2 years of follow-up * A subset of the control arm women who are in the crossover immunogenicity subcohort will be followed the full 6 years * Some women who received HPV vaccination and were not invited into the LTFU protocol (stopped attending their screening visits during CVT, discontinued their study participation during CVT or lived outside the study area) will be invited to participate in the LTFU protocol, particularly those who received an incomplete vaccination schedule * UNVACCINATED CONTROL GROUP: * Born in or between July 1978 and November 1987 * Residents of Guanacaste Province and a few areas of Puntarenas closest to Guanacaste at some point during 2005 * Able to speak/understand Spanish * Apparently mentally competent * Written informed consent obtained prior to enrollment Exclusion Criteria: * History of cervical cancer * History of hysterectomy * Any important medical condition or other criteria that the investigator considers that precludes enrollment * Vaccination with Ga…