Cost-Effectiveness of the Use of Adjuvanted Quadrivalent Seasonal Influenza Vaccine in Older Adults in Ireland

Abstract

Background: Enhanced vaccines (e.g., containing adjuvants) have shown increased immunogenicity and effectiveness in older adults, who often respond sub-optimally to conventional influenza vaccines. In this study, we evaluated the cost-effectiveness of an inactivated, seasonal, MF59-adjuvanted quadrivalent influenza vaccine (aQIV) for use in adults ≥ 65 years in Ireland. Methods: A published dynamic influenza model incorporating social contact, population immunity, and epidemiological data was used to assess the cost-effectiveness of aQIV in adults ≥ 65 years of age compared with a non-adjuvanted QIV. Sensitivity analysis was performed for influenza incidence, relative vaccine effectiveness, excess mortality, and the impact on bed occupancy from co-circulating influenza and COVID-19. Results: The use of aQIV resulted in discounted incremental cost-effectiveness ratios (ICERs) of EUR 2420/quality-adjusted life years (QALYs) and EUR 12,970/QALY from societal and payer perspectives, respectively, both of which are below the cost-effectiveness threshold of EUR 45,000/QALY. Sensitivity analysis showed that aQIV was effective in most scenarios, except when relative vaccine effectiveness compared to QIV was below 3%, and resulted in a modest reduction in excess bed occupancy. Conclusion: The use of aQIV for adults ≥ 65 years old in Ireland was shown to be highly cost-effective from both payer and societal perspectives.

Use of Adjuvanted Quadrivalent Influenza Vaccine in Older-Age Adults: A Systematic Review of Economic Evidence

“…The level of detail provided regarding model structure and rationale for the choice of parameter values used in the models varied and no studies included an open-access model alongside the paper. For example, one paper [18] directed readers to a full health technology assessment (HTA) document published in the Italian language, whereas another [24] referred readers to other published literature sources where information on parameter estimates were available. Kohli et al (2022) provided a detailed technical appendix.…”

“…Database searches returned 124 records; from this, 40 duplicates were removed, leaving 84 reports. Fourteen papers were assessed against the inclusion and exclusion criteria, resulting in 10 full-text papers for inclusion in the review [17][18][19][20][21][22][23][24][25][26]. The PRISMA 2020 diagram is presented in Figure 1.…”

“…All studies (as per the eligibility criteria) were in English and involved the comparison of an adjuvanted quadrivalent influenza vaccine against a relevant comparator in a population of older persons. All studies were conducted in high-income countries, namely, Italy [18,26], Spain [19,21,25], Norway, Denmark, Sweden [22], the United Kingdom [17], Germany [20], Belgium [23], and Ireland [24], and all studies were funded/supported by a pharmaceutical company and/or included industry employees as authors. The study population was individuals aged 65 years and older for all studies.…”

“…), allowing differential risk of complications with increasing age to be examined. For some of the analyses [17][18][19][20]24], influenza transmission was simulated using a deterministic Susceptible-Exposed-Infectious-Removed (SEIR) model to calculate attack rates of confirmed seasonal influenza infection by age group and viral subtype over the seasons considered. Models adopting this approach included all age groups (accounting for "herd immunity"), as opposed to models that included only the population under consideration [21][22][23]25,26].…”

“…Three studies compared aQIV with standard-dose QIV [18,19,24], three papers compared aQIV to high-dose QIV [17,21,26], three compared aQIV with both standard-dos QIV and high-dose QIV [20,22,23], and one study compared aQIV with recombinant QIV [25].…”