Long-term efficacy of a human papillomavirus type 16 vaccine

This dissertation includes three chapters. Chapter 1 provides the results of a study to evaluate the efficacy and immunogenicity of a prophylactic monovalent L1 virus-like particle (VLP) human papillomavirus (HPV) type 16 vaccine against incident HPV-16 infection and HPV-16-related cervical intraepithelial neoplasia (CIN) eight and one-half years after its administration, the longest duration of follow-up reported to date. In the primary efficacy population, the vaccine was 96% (95% confidence interval [CI]: 73%-100%) and 100% (95% CI: 43%-100%) efficacious against HPV-16 acquisition and HPV-16-related CIN, respectively, and 86% of vaccine recipients had remained HPV-16 seropositive. Chapter 2 provides the results of a study to evaluate the performance of oral mucosal transudate (OMT) for monitoring antibody levels in women who had received prophylactic HPV L1 VLP vaccines. Compared with serum, OMT was found to be 50% sensitive (95% CI: 42%-57%) and 100% specific (95% CI: 76%-100%) eight and one-half years after administration of the prophylactic HPV-16 vaccine. Six months after administration of the licensed prophylactic HPV-6/11/16/18 vaccine, OMT antibody levels rose substantially (Sensitivity = 100%; 95% CI: 92%-100%). Chapter 3 provides a review of difficulties in estimating the male-to-female sexual transmissibility of HPV infection, an important piece of information for determining the potential public health impact of prophylactic HPV vaccines.