Cost-Effectiveness Analysis of the High-Dose Trivalent Influenza Vaccine in the Elderly Population in Italy

Purpose: Influenza is a significant public health concern, particularly among the elderly, contributing to high morbidity, hospitalizations, and mortality, in addition to increased economic burden sustained by the Italian National Health Service (SSN). Traditional vaccines, ie, standard-dose trivalent inactivated influenza vaccine (TIV-SD), showed lower immunogenicity and effectiveness in older adults than in younger adults, as a result of the immunosenescence process and increased comorbidities. Enhanced formulations, such as the high-dose trivalent influenza vaccine (TIV-HD), have been introduced to address this gap. This study evaluates the cost-effectiveness of TIV-HD compared to TIV-SD for individuals ≥ 65 years of age in Italy. Patients and Methods: A cost-effectiveness analysis was performed using a population-based decision-analytic model from the perspective of the SSN, over a one-year time horizon. The model simulated clinical pathways for influenza-related events, including general practitioner visits, emergency department consultations, hospitalizations for cardiorespiratory complications, and mortality. Epidemiological and cost data were sourced from national databases and peer-reviewed literature. Three pricing scenarios were explored. The outcomes included life-years (LYs), quality-adjusted life years (QALYs), and healthcare costs, allowing the calculation of the incremental cost-effectiveness ratio (ICER). Results: Model-based results showed that TIV-HD is a dominant strategy over TIV-SD, yielding both improved health outcomes (14,070 LYs and 13,678 QALYs) and cost savings in all the pricing scenarios explored. When applied to the Italian elderly population eligible for seasonal influenza vaccination, TIV-HD was estimated to generate overall savings ranging from € 82.3 million and € 135.0 million for the National Health Service, driven by the prevention of approximately 50,000 influenza-related hospitalizations. Conclusion: This analysis indicates that TIV-HD was associated with improved outcomes and lower overall costs compared with TIV-SD under the modeled assumptions. The enhanced clinical effectiveness combined with significant cost reductions underscores TIV-HD as a cost-effective intervention, contributing to sustainable healthcare management in Italy. Plain Language Summary: Why was this study done? Every year in Italy, thousands of people aged 65 and over are hospitalized or die from flu-related complications. Standard flu vaccines may not work as well in older people because the immune system becomes weaker with age. A vaccine called the “high-dose trivalent influenza vaccine” (TIV-HD) was developed to improve the immune response in this age group. This study examined whether this vaccine offers good value for money for the Italian healthcare system. What did the researchers do and find? The researchers used a computer model to compare the standard-dose vaccine (TIV-SD) with the high-dose vaccine (TIV-HD) in people aged 65 and older. They looked at the number of flu cases, hospital visits, and deaths, as well as the costs to the National Health Service. The model estimated that, compared with TIV-SD, TIV-HD was associated with about 70,000 fewer flu cases, 50,000 fewer hospitalizations, and 1,400 fewer deaths each year. Although the high-dose vaccine costs more per dose, it was associated with estimated net cost savings ranging from € 82 to € 135 million, mainly due to fewer influenza-related events and hospitalizations. What do these results mean? The findings suggest that the high-dose vaccine may improve health outcomes while reducing healthcare costs in people aged 65 and over in Italy. These results indicate that the high-dose vaccine may represent an effective option to prevent flu in this age group, with potential savings for the healthcare system. Keywords: TIV-HD, influenza vaccination, cardiovascular worsening, costs, quality of life