Cost–effectiveness analysis of influenza vaccination for people aged 65 and over in Japan

In 2001, Japan launched a national influenza immunisation program for the elderly which provides a subsidy. In order to evaluate the efficiency of the strategy taken in this current program which provides 71% subsidy for all and explore alternative strategies, authors carried out a cost–effectiveness analysis. Authors compared strategies with different levels of subsidy and the use of risk-base targeting by constructing a decision tree model based on the literature. Incremental cost–effectiveness ratios of alternative strategies were estimated deterministically and probabilistically from societal perspective. Probabilistically estimated mean incremental cost–effectiveness ratio of current strategy is US$ 15,535 per YOLS, which can be concluded that current program is cost–effective. Authors also conclude that switching from current strategy to strategy which provides 100% subsidy for all, or strategy which provides 100% subsidy for high-risk elderlies only, can be cost–effective as well.