To compare the epidemiological and economic impact of additional cross-protection against oncogenic human papillomavirus (HPV) types beyond 16/18 of the bivalent vaccine (BV) versus protection against nononcogenic HPV types 6/11 of the quadrivalent vaccine (QV) in Taiwan.
A lifetime Markov model calibrated to the Taiwanese setting simulated the natural history of low-risk (engendering cervical intraepithelial neoplasia [CIN] 1 and genital warts) and high-risk HPV (engendering CIN1, CIN2/3, and cervical cancer [CC]) infections, screening, and vaccination (100% coverage) for a cohort of 12-year-old girls (N = 153,000). Transition probabilities, costs, and utilities were estimated from published data and expert opinion. Vaccine efficacy was obtained from each vaccine's respective clinical trials. Price-parity and lifelong protection was assumed for both vaccines. The number of CIN lesions, CC cases, CC deaths and genital wart (GW) cases, and quality-adjusted life-years were estimated. Costs and outcomes (discounted at 3% and 1.5%, respectively) were compared from a payer's perspective.
The model estimated that the BV led to an additional, undiscounted, 11,484 CIN1, 1,779 (+34.3% vs. QV) CIN2/3, 188 (+29.0% vs. QV) CC, and 69 (+29.0% vs. QV) CC deaths prevented compared with the QV, while the QV prevented 4,150 GW (+71%). This resulted in an additional 768 quality-adjusted life-years (QALY) and 11.6 million new Taiwan dollars costs saved for the BV versus the QV after discounting.
Both vaccines have a different epidemiological impact with an increased number of CC-related lesions potentially prevented for the BV because of additional cross-protection. In the Taiwanese setting, HPV mass vaccination using the BV was estimated to dominate vaccination using the QV.