Abstract
INTRODUCTION: Emerging evidence of durable immunogenicity from mono-dose human papillomavirus vaccination (HPVV) prompted the WHO to recommend a single-dose HPVV schedule in December 2022. There is, however, limited understanding of processes and considerations influencing country adoption of the updated HPVV dosing schedule recommendation. METHODS: We identified four archetypes characterising countries' progress along the HPVV introduction and single-dose adoption continua. From September 2023 to February 2024, we purposefully sampled and conducted semistructured interviews with immunisation stakeholders representing Ministries of Health, Gavi-funded technical assistance partners, civil society organisations and multilateral agencies from African and Asian low-income and middle-income countries. Using multicycle, iterative thematic analysis, we identified factors enabling the adoption of the HPVV single-dose recommendation, as well as constraints to rendering a decision on the HPVV dosing schedule. RESULTS: We interviewed 66 stakeholders across 19 countries with mature HPVV programmes (n=11) or forthcoming national HPVV introductions (n=8), as well as countries adopting (n=10) or undecided about (n=9) the single-dose schedule. Stakeholders conveyed enthusiasm for single-dose HPVV, citing the following anticipated benefits: higher HPVV schedule completion and coverage, especially in underimmunised populations; costs saved from operational reconfigurations and reduced vaccine procurement demands, particularly for countries transitioning out of Gavi co-financing in a vaccine supply-constrained environment; and optimised vaccine stock management capacity, importantly for countries pursuing new vaccine introductions for multiple antigens simultaneously. Factors demotivating HPVV single-dose schedule adoption or delaying decision-making included: limited localised evidence of long-term immunologic protection from single-dose HPVV; off-label product use liabilities; costs/resources required for retraining the health workforce in countries with mature HPVV programmes; and potential for widening HPVV coverage inequities, notably in countries with elevated HIV burdens. CONCLUSIONS: Coupled with the WHO's endorsement, the perceived benefits of single-dose HPVV consistently outweighed the anticipated risks, even when these risks delayed country-level HPVV schedule-related decision-making.