Methodological drivers, reporting completeness, and transferability in HPV vaccination economic evaluations: A scoping review

BACKGROUND: Human papillomavirus (HPV) vaccination is widely reported as cost-effective, but reported incremental cost-effectiveness ratios (ICERs) are shaped by model structure, assumptions, comparator choice, vaccine price, threshold selection, and local screening context. Previous reviews have summarized cost-effectiveness findings but have less often examined why conclusions differ across settings. OBJECTIVE: To map methodological evolution, drivers of variation, reporting completeness, methodological credibility, and transferability in HPV vaccination economic evaluations. METHODS: A scoping review was conducted using the methodological framework proposed by Arksey and O'Malley, refined by Levac et al., and informed by JBI guidance for scoping reviews. Reporting followed PRISMA-ScR, and the protocol was preregistered on the Open Science Framework (OSF). PubMed, Scopus, PsycINFO, Embase, Web of Science, and CINAHL were searched from January 1, 2003, to December 31, 2025, with a final search conducted on January 2, 2026. Forty-four records were mapped. Thirty-three full comparative economic evaluations formed the primary synthesis; 11 partial or non-standard economic evidence records were retained as contextual evidence. The Consolidated Health Economic Evaluation Reporting Standards 2022 (CHEERS 2022) checklist was applied retrospectively to assess reporting completeness, and a descriptive structured appraisal was used to examine methodological credibility across six health-economic domains. A Welte-informed assessment was used to examine target-context contextualization. RESULTS: The evidence base evolved from early static cohort models to dynamic transmission and individual-based approaches, while static models remained common in LMIC-focused standardized-tool analyses. The main drivers of variation were vaccine price, discounting, herd-immunity assumptions, cross-protection assumptions, and threshold selection. Reporting completeness varied and did not necessarily correspond to methodological credibility. Relevance to a study's own decision setting did not imply that its ICER could be transferred to other countries. Eleven contextual records showed emerging policy questions around delivery costs, fiscal consequences, uptake, risk-benefit framing, and non-ICER-based decision support. CONCLUSION: The economic value reported for HPV vaccination depends on the assumptions, comparators, vaccine prices, thresholds, and local screening contexts used in each evaluation rather than on the vaccine alone. Future evaluations should explicitly justify the choice of comparator, model structure, vaccine-price assumptions, discount rates, thresholds, uncertainty analysis, and transferability assumptions. Although formal cost-effectiveness analyses of single-dose HPV vaccination have begun to emerge, evidence remains limited, particularly regarding durability, waning, delivery feasibility, gender-neutral vaccination in LMICs, and country-specific evaluations in underrepresented regions.