Cost-Effectiveness of Bivalent Prefusion F Vaccine for Prevention of Respiratory Syncytial Virus Among Older Adults in Italy

Sergio Di Matteo,1 Paolo Bonanni,2 Sara Boccalini,2 Roberto Di Virgilio,3 Emma Lucia Fogliati,1 Giorgio Lorenzo Colombo4,5 1Center of Research, SAVE Studi - Health Economics and Outcomes Research, Milan, Italy; 2Department of Health Sciences, University of Florence, Florence, Italy; 3Pfizer Italia srl, Rome, Italy; 4Department of Drug Sciences, University of Pavia, Pavia, Italy; 5CEFAT- Department of Drug Sciences University of Pavia, Center of Pharmaceuticals Economics and Medical Technologies Evaluation, Pavia, ItalyCorrespondence: Giorgio Lorenzo Colombo, Department of Drug Sciences, University of Pavia, Pavia, Italy, Email [email protected]: Respiratory syncytial virus (RSV) represents a significant health threat for older adults and individuals with comorbidities. RSV infection is often underdiagnosed, limiting the understanding of its clinical and economic burden. The approval of the bivalent RSV prefusion F vaccine offers a new preventive strategy. This study evaluated its cost-effectiveness to optimize resource allocation in Italy.Materials and Methods: A Markov cohort model was developed to assess the cost-effectiveness of vaccinating adults with a single dose of RSVpreF vaccine versus no vaccination, from the perspective of the Italian National Health Service (NHS). Two vaccination scenarios were analyzed: a base-case scenario assuming implementation of the vaccination strategy in the general population aged 75– 99 years, and an alternative scenario focusing on adults aged 60– 74 years with comorbidities. A vaccination coverage rate of 52.5% was assumed, according to the rate recorded among individuals over 65 years during the 2024/2025 season. Model outcomes included RSV cases, hospitalizations, deaths, direct medical costs, quality-adjusted life years (QALYs) and incremental cost-effectiveness ratio (ICER). To test the robustness of the results, deterministic sensitivity analysis (DSA) and probabilistic sensitivity analysis (PSA) were conducted.Results: In base-case scenario, the analysis indicated that vaccination with RSVpreF vaccine could have prevented 314,486 RSV cases and 7163 deaths, resulting in gains of 41,638 LYs and 30,317 QALYs. The ICER was € 10,662 per LY gained and € 14,644 (range: € 9021 to € 21,740) per QALY gained. In the alternative scenario the model estimated the prevention of 221,600 RSV cases and 2567 deaths, resulting in gains of 28,429 LYs and 20,395 QALYs. The ICER was € 11,211 per LY gained and € 15,628 (range: € 9597 to € 21,965) per QALY gained. Both scenarios proved to be cost-effective.Conclusion: Vaccinating with RSVpreF vaccine has shown substantial clinical and economic benefits. These findings support the inclusion of RSV vaccination in national immunization programs for older populations.Keywords: RSV, economic evaluation, cost-utility, vaccination, RSVpreF vaccine, pharmacoeconomics