Cost-Effectiveness and Budget Impact Analysis of the Trivalent Adjuvanted Influenza Vaccine in People over 50 Years of Age for Argentina

BACKGROUND: Influenza imposes a substantial burden on Argentina, particularly among adults aged 50-64 with comorbidities and those aged ≥65. The adjuvanted trivalent influenza vaccine (aTIV) has shown superior effectiveness compared with non-adjuvanted vaccines; however, its cost-effectiveness and budget impact in the 50-64 high-risk population have not been assessed nationally. This study evaluates the cost-effectiveness and budget impact of introducing aTIV for high-risk adults aged 50-64, alongside its use in adults aged ≥65, compared with standard-dose trivalent influenza vaccine (SD-TIV) from the Argentine health care system perspective. METHODS: A decision-analytic static model was used to compare aTIV with SD-TIV over a single influenza season. In addition, a 5-year budget impact analysis (BIA) was conducted under scenarios of progressive uptake. Model inputs were derived from international literature, local data, and expert opinion. Deterministic and probabilistic sensitivity analyses were performed. RESULTS: Compared with SD-TIV, aTIV yielded a lifetime gain of 1489 quality-adjusted life-years (QALYs) at an incremental cost of USD 8.34 million, resulting in an incremental cost-effectiveness ratio (ICER) of USD 5599 per QALY gained-well below Argentina's cost-effectiveness threshold (USD 11,059/QALY). Higher vaccine acquisition costs were largely offset by reductions in outpatient visits and hospitalizations. The BIA showed a modest average annual per-member-per-month increase of USD 0.0025, remaining below the estimated budget impact threshold (USD 0.0065). CONCLUSIONS: Implementing aTIV in adults aged ≥50 with risk factors would be cost-effective and affordable in Argentina. These findings support the consolidation and potential expansion of current vaccination strategies to reduce influenza burden.