Early impact of HPV vaccination at the population level

The broad aim of this dissertation is to understand the early impact of HPV vaccination in females at the population level. Three important public health questions are addressed: 1) Is HPV vaccination doing what is expected: decreasing the prevalence of vaccine-type HPV 6, 11, 16 and 18 which are etiologically linked to invasive cervical cancer and genital warts?; 2) Is there evidence of beneficial cross-protection (decreased prevalence) of any of the other non-vaccine-targeted high-risk (HR) HPV genotypes?; and 3) With the expected decline of HPV 16 and 18, are there deleterious virological consequences, such as type-replacement (increased prevalence) with a rise of non-vaccine-targeted HR HPV? In the first chapter, I assess and synthesize peer-reviewed literature published from 2007 to 2013 that documented early impact of HPV vaccination. Seventeen ecological studies were stratified into three tiers based on degree of vaccination impact (cervical abnormalities, genital warts, and HPV DNA) and incidence or prevalence in samples from a pre-HPV vaccination time period (pre-2007) with that of a post-vaccination time period (post-2007) were compared. In the second chapter, I investigate vaccine-type HPV prevalence changes between pre- and post-vaccine periods in over 8,000 females aged 14-59 years enrolled in the NHANES HPV Vaginal Swab Surveys from 2003-2010. In the third chapter, I test for evidence of non-vaccine-targeted HR HPV genotypic cross-protection and type-replacement in NHANES Survey females from the pre- and post-vaccine periods. Finally, I conclude the dissertation with a summary of the findings and a discussion of the public health impltcations and offer suggestions for future research.