Estimating the long-term clinical impact of cervical cancer vaccination in Taiwan.

The high burden of human papillomavirus (HPV) infection and subsequent cervical cancer in the presence of screening in Taiwan suggests the need for further prevention strategies. Epidemiology and screening practices vary considerably between countries, and specific analyses are required to estimate the impact of HPV vaccination. This study adapted a computer-based health economic model to Taiwan to project the clinical impact of the introduction of a prophylactic vaccine against persistent HPV 16/18 infection on cervical disease. A Markov model based on the natural history of HPV and cervical cancer was developed to simulate transitions between health states (normal, HPV, cervical intraepithelial neoplasia [CIN] stages I to III, cervical cancer stages I to IV, and death) in the presence of screening. The model was calibrated to Taiwan epidemiological end points including age-specific HPV prevalence, prevalence of CIN lesions, and predicted cervical cancer incidence and mortality. Taiwanese screening and treatment practices were modeled, and published clinical trial data were used to estimate vaccine efficacy. With 100% vaccine coverage in a 13-year-old cohort of females, there is estimated to be a 71% reduction in cervical cancer cases and deaths due to all HPV types and substantial reductions in the prevalence of precancerous lesions and screening outcomes. Removing the risk of HPV infection of a large proportion of Taiwanese females, with a high underlying cervical cancer incidence rate, would be expected to have dramatic effects on the health care system and mortality in Taiwan.