Economic evaluation of high-dose inactivated influenza vaccine in adults aged ≥65 years: A systematic literature review

INTRODUCTION: Due to waning immunity, adults aged ≥65 years are at increased risk of seasonal influenza infection and its complications. Adding to this risk, older adults have reduced responses to influenza vaccines. A high-dose trivalent inactivated influenza vaccine (Fluzone High-Dose, Sanofi Pasteur) (IIV3-HD) was developed to improve protection against influenza in adults aged ≥65 years and has been licensed in the US since 2009 and in Canada since 2015. Post-licensure studies have shown that IIV3-HD is more effective than standard-dose trivalent inactivated influenza vaccine (IIV3-SD) at protecting against influenza infection in this population. Here, we performed a systematic review of economic analyses of IIV3-HD in adults aged ≥65 years. METHODS: On June 9, 2019, using the Ovid search platform, we searched Econlit, Embase, and Ovid MEDLINE® for original studies published in peer-reviewed journals examining the economics or cost-effectiveness of IIV3-HD in adults aged ≥65 years. Two reviewers independently selected studies and assessed their quality. RESULTS: Seven studies were selected, all performed in the US or Canada. Five studies were funded by IIV3-HD manufacturer, and the remaining two by the US National Institute of General Medical Sciences. In all studies, IIV3-HD reduces healthcare resource utilization and is cost-effective or cost-saving compared to IIV3-SD. The main driver is reduced hospitalizations for cardiorespiratory events. CONCLUSION: IIV3-HD is cost-saving or cost-effective versus IIV3-SD in adults aged ≥65 years. Reduced cardiorespiratory complications are an important driver of these economic benefits. A video summary of the article can be accessed via the Supplementary data link at the end of this article.