OBJECTIVES: Enhanced influenza vaccines are the best option for the elderly. In 2021, Argentina introduced the MF59-adjuvanted inactivated influenza vaccine (aIIV) for individuals aged 65yrs and above. High dose inactivated influenza vaccine (HD-IIV) is also currently registered. This study evaluates the clinical and economic outcomes of these noted enhanced influenza vaccines for the elderly in Argentina.

METHODS: Using a static decision-tree model and adopting the payer's perspective during an average influenza season, the analysis incorporated influenza epidemiological data from pre-pandemic Argentinian seasons (2014–2019), strain distribution, vaccination uptake, and influenza-related costs and Quality-Adjusted Life-Years (QALYs). Results include two relative vaccine effectiveness (rVE) scenarios from two published meta-analyses due to reported variability without statistical significance expected. Vaccination acquisition costs were obtained from aIIV manufacturer, while HD-IIV costs were estimated using local (Argentinean private sector) and international public sector data (Europe). This assessment considered the WHO criteria for cost-effectiveness thresholds in developing countries—one GDP per-capita (US$13,696). This assessment includes deterministic and probabilistic sensitivity analyses.

RESULTS: With an expected lower vaccine cost and non-significant higher rVE for aIIV (3.2%), aIIV increased the overall number of QALYs in 41.4 and generated savings to the Argentinean public health system in US$1.7M. In this scenario aIIV resulted as a dominant strategy over HD-IIV. On a second scenario, were HD-IIV has a non-significant higher rVE compared to aIIV (15.9% vs 13.9%, vs standard-dose IIV), HD-IIV will only result cost-effective compared to aIIV if its public price is below 50% in relation to incremental cost to the standard-dose IIV acquisition price.

CONCLUSIONS: In Argentina, the use of enhanced influenza vaccines in the elderly can increase vaccine effectiveness, reduce mortality and disease-related costs. Based on comparable vaccine effectiveness, significant economic advantages favor the MF59-adjuvanted inactivated influenza vaccine strategy due its expected lower acquisition costs.