Pharmacoeconomic evaluation of the MF59--adjuvanted influenza vaccine in the elderly population in Italy.

INTRODUCTION Influenza vaccination has proven effective in the reduction of influenza-like illness (ILI) cases and influenza-related hospitalizations, drug consumption, primary care consultations and deaths in the elderly population. The aim of this study is the assessment of the financial budget impact of a seasonal vaccination program based on the use of the MF59 adjuvanted vaccine as compared with the traditional vaccine or the absence of vaccination in Italian elderly population. METHODS A pharmacoeconomic simulation model was developed to simulate the effect of the three different vaccination programs during a single influenza season. Health economics and demographic data were taken from specific Italian sources, and vaccine effectiveness data derived from published literature. Direct medical costs were considered according to current Italian prices and tariffs. RESULTS About 83% of the 12 million people of at least 65 years of age currently resident in Italy can be considered at high risk for influenza complications due to underlying chronic diseases. Absence of vaccination could lead to more than 2 million ILl cases, and 29,000 related deaths. The vaccination program with a coverage rate of 65.6% would lead to an estimated 1.5 million ILl cases (26.9% reduction) with a standard vaccine and to 1.3 million (35.8% reduction) with the MF59 adjuvanted vaccine with a relative increase of avoided cases of 33,1%. The standard vaccination program produced a moderate direct cost increase of about 50 million Euro (+4.6%), whereas the adjuvanted vaccine provided an estimated saving of about 74 million Euro (-6.8%), both compared to the non vaccination. Cost savings were mainly related to hospital admissions avoided in the elderly population (>or=65 years of age). CONCLUSIONS The vaccination with the MF59 adjuvanted vaccine resulted more effective and cost saving when compared with the standard vaccination and with no vaccination, thus representing the optimal strategy for the elderly population. The standard vaccine, even though a light cost increase, still proved to be effective compared to the null option, with the initial cost for the vaccination program nearly offset by healthcare resources savings obtained during the season.