Estimates of the timing of reductions in genital warts and high grade cervical intraepithelial neoplasia after onset of human papillomavirus (HPV) vaccination in the United States

Background: The objective of this study was to estimate the number of years after onset of a quadrivalent HPV vaccination program before notable reductions in genital warts and cervical intraepithelial neoplasia (CIN) will occur in teenagers and young adults in the United States. Methods: We applied a previously published model of HPV vaccination in the United States and focused on the timing of reductions in genital warts among both sexes and reductions in CIN 2/3 among females. Using different coverage scenarios, the lowest being consistent with current 3-dose coverage in the United States, we estimated the number of years before reductions of 10%, 25%, and 50% would be observed after onset of an HPV vaccination program for ages 12-26 years. Results: The model suggested female-only HPV vaccination in the intermediate coverage scenario will result in a 10% reduction in genital warts within 2-4 years for females aged 15-19 years and a 10% reduction in CIN 2/3 among females aged 20-29 years within 7-11 years. Coverage had a major impact on when reductions would be observed. For example, in the higher coverage scenario a 25% reduction in CIN2/3 would be observed with 8 years compared with 15 years in the lower coverage scenario. Conclusions: Our model provides estimates of the potential timing and magnitude of the impact of HPV vaccination on genital warts and CIN 2/3 at the population level in the United States. Notable, population-level impacts of HPV vaccination on genital warts and CIN 2/3 can occur within a few years after onset of vaccination, particularly among younger age groups. Our results are generally consistent with early reports of declines in genital warts among youth. Published by Elsevier Ltd.