Cost-effectiveness analysis of influenza vaccination with high-dose vaccine versus standard-dose quadrivalent vaccine in older adults in Spain

INTRODUCTION AND OBJECTIVES: Influenza is a widespread acute respiratory illness which represents a significant public health challenge from both the National Health Service (NHS) and societal perspective, especially in the older adults. The aim of this study was to assess the cost-effectiveness of influenza vaccination with a high-dose quadrivalent vaccine (HD-QIV) versus a standard dose quadrivalent vaccine (SD-QIV) in the older adults in Spain. METHODS: We assessed the public health and economic benefits of various alternatives using a decision-tree model. This model considered factors such as influenza cases, visits to general practitioners (GP), emergency department (ED) visits, hospitalizations due to cardiorespiratory events, and influenza-related mortality. To address uncertainties deriving from both epidemiological and economic sources, we conducted deterministic and probabilistic sensitivity analyses. RESULTS: From a societal perspective, HD-QIV compared to SD-QIV prevented during an influenza season 54,039 influenza cases, 7,733 GP consultations, 1,585 ED visits, 30,772 episodes of hospitalization due to cardiorespiratory events over a single influenza season and 1,203 deaths when vaccinating adults ≥ 65 years old in Spain, resulting in 14,316 LYs and 12,545 QALYs gained over a lifetime horizon. The reduction in health outcomes outweighed the increase in vaccination costs, translating to a reduction in total costs with HD-QIV compared to SD-QIV. Therefore, vaccinating older adults in Spain with HD-QIV instead of SD-QIV was a dominant strategy when evaluating hospitalizations due to cardiorespiratory events. HD-QIV remained dominant from an NHS perspective. Sensitivity analyses confirmed the robustness of the model. CONCLUSIONS: This analysis showed that vaccinating older adults in Spain with HD-QIV instead of SD-QIV would reduce cases of influenza, GP and ED visits, hospitalizations, deaths, and associated costs, and thus it should be the strategy of choice in a situation of budgetary constraints from either a societal or an NHS perspective.