Scoping review maps methodological drivers and transfer limits in HPV vaccination economic evaluations

A scoping review of HPV vaccination economic evaluations found that reported economic value depended on study assumptions and decision context as much as on the vaccine itself. Across 33 full comparative evaluations, the main recurring sources of variation were vaccine price, discount rates, herd-immunity modeling, vaccine efficacy and cross-protection assumptions, and the choice of cost-effectiveness threshold. The review also found that strong reporting did not necessarily indicate strong methodological credibility or that an incremental cost-effectiveness ratio could be transferred to another country.

The researchers searched PubMed, Scopus, PsycINFO, Embase, Web of Science and CINAHL for studies published from January 1, 2003, through December 31, 2025, with a final search conducted on January 2, 2026. They followed an Arksey and O’Malley framework refined by Levac and colleagues and informed by JBI scoping-review guidance, with reporting based on PRISMA-ScR. The protocol was preregistered on the Open Science Framework. Two reviewers independently screened records, assessed full-text eligibility and extracted data, resolving disagreements by discussion.

The searches returned 2,020 records. After removal of 1,285 duplicates and 548 records excluded under predefined administrative, publication-type, topic and economic-content filters, 187 records underwent title-and-abstract screening. Fifty-one reports were assessed in full text and seven were excluded, leaving 44 records published from 2004 through 2025. The mapped evidence covered more than 25 country contexts and five multi-country regional analyses across all six World Health Organization regions.

Of the 44 included records, 33 were full comparative economic evaluations comprising cost-effectiveness, cost-utility or formal cost-benefit analyses. These formed the primary synthesis. The other 11 were classified as contextual records because they presented partial or non-standard economic evidence, including cost-consequence, fiscal net present value, coverage-uptake, risk-benefit, delivery-cost and other policy-relevant analyses. They were mapped descriptively but were not combined with the formal incremental cost-effectiveness ratio synthesis.

Modeling methods did not follow a simple progression from static to dynamic approaches. The earliest period, 2004–2010, included nine full evaluations, predominantly static Markov cohort models. The 2011–2017 period included 12, with six static cohort, three dynamic transmission and three microsimulation models. The 2018–2025 group also included 12, including eight static cohort models, three dynamic transmission models and one individual-based microsimulation. Static models therefore remained common, particularly in standardized-tool analyses focused on low- and middle-income countries and in recent single-dose evaluations.

Five methodological factors were classified as recurring drivers of variation because studies identified them as influential in sensitivity analyses or because they repeatedly explained divergent results. These were vaccine price, discounting, herd-immunity modeling, efficacy and cross-protection assumptions, and threshold selection. Inclusion of indirect productivity costs was also recurring, particularly in cost-benefit, societal-perspective and fiscal analyses. Analytic perspectives ranged from healthcare payer and government perspectives to societal, fiscal and individual risk-benefit perspectives, affecting the inclusion of productivity, patient and broader fiscal costs.

Reporting completeness was assessed retrospectively against the 28-item CHEERS 2022 checklist. Using reviewer-defined descriptive bands, 15 evaluations were classified as high completeness, 16 as moderate and two as low, representing 45%, 48% and 6% of the 33 full evaluations, respectively. Mean completeness was 73.0% for 16 industry-funded records and 81.3% for 17 non-industry records. Completeness also differed by publication period, averaging 72.0% in 2004–2010, 76.8% in 2011–2017 and 81.6% in 2018–2025. These figures describe retrospective reporting and are not validated methodological-quality scores.

A separate descriptive appraisal assessed methodological credibility across comparator appropriateness, model structure, local calibration and validation, herd-immunity modeling where relevant, uncertainty analysis and threshold justification. Comparator appropriateness was rated adequate in 23 records and model-structure suitability in 21. Local calibration and validation was less consistent: 16 records were rated adequate, 13 partial and four limited. Formal probabilistic sensitivity analysis appeared in a minority of evaluations, mainly in high-income and microsimulation studies, while several low- and middle-income-country evaluations relied mainly on deterministic sensitivity analysis.

The analysis of transferability used a Welte-informed assessment of how strongly each evaluation reflected its target setting. Target-context contextualization did not consistently align with reporting completeness. Some highly complete evaluations were only moderately contextualized because they used regional models, extrapolated costs or common product-comparison frameworks, while some moderately complete evaluations were highly contextualized through country-specific epidemiology, screening, cost, surveillance or policy inputs. Differences in screening organization, cost inputs, vaccine-product assumptions, calibration and thresholds were therefore barriers to transfer in addition to missing reporting.

The review has several limitations. It excluded gray literature, health-technology-assessment reports, theses, conference abstracts and editorials, and included only English-language peer-reviewed publications. The CHEERS categories were not official quality bands; the methodological appraisal was a structured but nonvalidated descriptive exercise involving reviewer judgment. The model-lineage analysis did not test funding-related bias, and the review did not recalculate incremental cost-effectiveness ratios, standardize costs or pool results quantitatively. The mapped literature also contained limited formal evidence on single-dose vaccination, including questions about durability, waning, delivery feasibility, gender-neutral programs in low- and middle-income countries, and country-specific evidence from underrepresented regions.

Subject of Research: Methodological variation, reporting completeness and transferability in HPV vaccination economic evaluations

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

Article References: Kisa, A., & Kisa, S. (2026). Methodological drivers, reporting completeness, and transferability in HPV vaccination economic evaluations: A scoping review. PLOS One, 21(10), e0360732. https://doi.org/10.1371/journal.pone.0360732

Image Credits: AI Generated

DOI: 10.1371/journal.pone.0360732

Keywords: HPV vaccination, economic evaluation, cost-effectiveness, scoping review, CHEERS 2022, modeling methods, transferability, herd immunity, vaccine pricing, Methodological, drivers, reporting