Cost-effectiveness and public health impact of using high dose quadrivalent influenza vaccine in the French older adults population

BackgroundSeasonal influenza outbreaks in France cause a surge in patients, exacerbating the overburdened healthcare system each winter. Older adults are particularly vulnerable to serious events related to influenza. Quadrivalent influenza high dose (QIV HD) vaccines have been developed to offer better clinical protection in older adults, who often exhibit suboptimal immune response to quadrivalent influenza standard dose vaccines (QIV SD). This study aims to evaluate the public health impact and cost-effectiveness of administering HD versus SD vaccines to individuals aged 65+ in France. MethodologyUsing a static model and decision-tree approach, the study analyzed health outcomes such as influenza cases, GP (general practitioner) visits, hospitalizations, and mortality; relative vaccine efficacy (rVE) estimates were derived from a pivotal randomized-controlled trial and a meta-analysis comparing HD to SD vaccines. Two approaches were implemented to model hospitalizations (conditional on influenza or not), and analyses on bed occupancy were performed. ResultsResults showed that using QIV HD instead of QIV SD during an average influenza season in France led to the prevention of 57,209 additional cases of influenza, 13,704 GP visits, and 764 influenza-related deaths. Moreover, switching to QIV HD resulted in an additional 1,728-15,970 hospitalizations avoided and 15,124-138,367 reduced days of hospitalization depending on the hospitalization approach used. The cost-utility analysis showed a cost per quality-adjusted life year (QALY) gained ranging from 24,020 <euro>/QALY to 5,036 <euro>/QALY. ConclusionsSwitching to QIV HD in older adults was shown to be cost-effective, with even greater public health benefits at a higher coverage rate, regardless of the season severity.