Studio costo-efficacia della vaccinazione influenzale per gli italiani di età compresa tra 50 e 64 anni

Background: In 1999, the American Academy of Family Physicians already included, among target groups for influenza vaccination, subjects aged 50-64 years, because of the increased prevalence of people with high-risk conditions in this age group. However, studies on the cost-effectiveness and cost-utility of influenza vaccination in this population are necessary in order to provide useful indications for Public Health decision makers. Methods: In this study, we built a probabilistic model to evaluate the cost-effectiveness of reimbursement only for adults aged 50-64 years with high-risk conditions, in comparison with reimbursement for all individuals in this age group, in Italy. Model inputs were obtained from the international and national literature, web-sites and the Italian network for influenza surveillance (CIRINET-INFLUNET). Results: The model revealed benefits from vaccination in the form of decreased rates of influenza cases, hospitalizations and deaths from influenza, more life expectancy and quality-adjusted life years (QALYs). In the case of reimbursement for all people aged 50-64 years, the incremental cost-effectiveness ratio (ICER) was € 15,652 per QALY for a third-party payer (TPP) and the vaccination program was cost-saving for the society. This immunization strategy should avoid 95,813 cases of influenza-like illnesses, 232 deaths, 3,235 hospitalizations and 111,981 workdays lost. Assuming a cost-effectiveness threshold ratio of € 50,000 per QALY gained, the probability of the new strategy being cost-effective was 89% for the TPP and 99% for society. Conclusions: Lowering the age threshold for routine influenza vaccination from 65 to 50 years is likely to be cost-effective and not too expensive for the National Health System.