Cost-effectiveness of high-dose influenza vaccination in the Netherlands: Updated analysis incorporating new evidence

Background High-dose inactivated influenza vaccination (HD-IIV) has demonstrated superior effectiveness versus unadjuvanted standard-dose vaccination (SD-IIV) in older adults. A recent meta-analysis integrated complementary evidence sources representing over 85 million individuals across 15 influenza seasons. Methods A previously developed model was updated using lifetime horizon and societal perspective. Updated parameters included demographics, costs, hospitalization rates, and relative vaccine effectiveness (rVE): RCT evidence (24% for influenza-like illness, 7% for cardiorespiratory hospitalizations) and RCT + real-world evidence (RWE) (15% for ILI, 8% for cardiorespiratory hospitalizations). Results HD-IIV resulted in incremental cost-effectiveness ratios of €7300/QALY (RCT evidence) and €5800/QALY (RCT + RWE evidence). HD-IIV implementation in adults ≥60 years old would prevent 7200 general practitioner visits, 6300 cardiorespiratory hospitalizations, and 269 deaths. Probabilistic sensitivity analysis demonstrated >99% probability of cost-effectiveness at €20,000/QALY threshold. Conclusions HD-IIV remains highly cost-effective for adults aged ≥60 years under updated evidence scenarios, supporting implementation in the Dutch immunization programme.