Systematic Review on the Cost-Effectiveness of Seasonal Influenza Vaccines in Older Adults

Objectives: Older adults are at high risk of influenza-related complications or hospitalization. The purpose of this systematic review is to assess the relative cost-effectiveness of all influenza vaccine options for older adults. Methods: This systematic review identified economic evaluation studies assessing the cost-effectiveness of influenza vaccines in adults >= 65 years of age from 5 literature databases. Two reviewers independently selected, extracted, and appraised relevant studies using the JBI Critical Appraisal Checklist for Economic Evaluations and Heyland's generalizability checklist. Costs were converted to 2019 Canadian dollars and adjusted for inflation and purchasing power parity. Results: A total of 27 studies were included. There were 18 comparisons of quadrivalent inactivated vaccine (QIV) versus trivalent inactivated vaccine (TIV): 5 showed QIV dominated TIV (ie, lower costs and higher health benefit), and 13 showed the results depended on willingness to pay (WTP). There were 9 comparisons of high-dose TIV (TIV-HD) versus TIV: 5 showed TIV-HD dominated TIV, and 4 showed the results depended on WTP. There were 8 comparisons of adjuvanted TIV (TIV-ADJ) versus TIV: 4 showed TIV-ADJ dominated TIV, and 4 showed the results depended on WTP. There were few pairwise comparisons among QIV, TIV-HD, and TIV-ADJ. Conclusions: The evidence suggests QIV, TIV-HD, and TIV-ADJ are cost-effective against TIV for a WTP threshold of $50 000 per quality-adjusted life-year. Future studies should include new and existing vaccine options for broad age ranges and use more robust methodologies-such as real-world evaluations or modeling studies accounting for methodological, structural, and parameter uncertainty.

Automated summary

Older adults are at high risk of influenza-related complications or hospitalization. This systematic review evaluates the cost-effectiveness of different influenza vaccine options for older adults. The findings suggest that quadrivalent inactivated vaccine (QIV), high-dose trivalent inactivated vaccine (TIV-HD), and adjuvanted trivalent inactivated vaccine (TIV-ADJ) are cost-effective compared to trivalent inactivated vaccine (TIV), with a willingness to pay threshold of $50,000 per quality-adjusted life-year. Future studies should employ robust methodologies, such as real-world evaluations or modeling studies, to account for methodological, structural, and parameter uncertainty.