[Budget Impact Analysis of the Adjuvanted Quadrivalent Influenza Vaccine in the Elderly in Italy]

BACKGROUND: Vaccination is the most effective way to prevent influenza and its complications. The MF59-adjuvanted quadrivalent (aQIV) and the high-dose quadrivalent (QIV-HD) influenza vaccines have been specifically developed to protect subjects aged ≥65 years. The aim of this study was to evaluate the economic consequences associated with the use of aQIV in the elderly population in Italy.METHODS: An Excel-based budget impact model was developed to estimate the costs of aQIV for the prevention of influenza and its complications in elderly subjects, from the perspective of the Italian National Health Service. In the base-case analysis a current scenario (with aQIV) was compared with a past scenario (without aQIV), in which only the standard quadrivalent influenza vaccine (QIV-STD) was available. In the scenario analysis, a current scenario was compared with a future (hypothetical) scenario, in which the market share of aQIV grows. Efficacy (or effectiveness) data of vaccines, in terms of reduction of influenza-related deaths and hospitalizations for influenza/pneumonia, respiratory, and cardiac complications, were obtained from the scientific literature. Relative effectiveness of aQIV and QIV-HD vs. QIV-STD in preventing laboratory-confirmed influenza cases came from two meta-analysis of real-world studies. Epidemiological data and unit costs are collected from Italian published sources.RESULTS: In the base-case analysis the introduction of aQIV e QIV-STD was associated with a reduction of influenza and influenza-like illness – ILI (-93,171) cases, hospitalization for influenza, respiratory and cardiovascular complications (-6,823), and deaths (-1,841) and a consequent saving of € 1.9 million and € 24 million related to events and hospital admissions avoided, respectively. In the scenario analysis, the growth of the market shares of aQIV was associated with 13,602 fewer cases of influenza and ILI, 996 fewer hospitalizations, and an overall saving equal to € 3.8 million.CONCLUSIONS: aQIV reduces the number of cases of influenza and ILI, hospitalizations for influenza and respiratory or cardiac complications, and deaths in the Italian population aged ≥65 years.