Comparing the Clinical and Economic Outcomes Associated with Adjuvanted versus High-Dose Trivalent Influenza Vaccine among Adults Aged ≥ 65 Years in the US during the 2019–20 Influenza Season—A Retrospective Cohort Analysis

Abstract

The burden of influenza is disproportionally higher among older adults. We evaluated the relative vaccine effectiveness (rVE) of adjuvanted trivalent (aIIV3) compared to high-dose trivalent influenza vaccine (HD-IIV3e) against influenza and cardio-respiratory disease (CRD)-related hospitalizations/ER visits among adults ≥65 years during the 2019–2020 influenza season. Economic outcomes were also compared. A retrospective cohort analysis was conducted using prescription, professional fee claims, and hospital data. Inverse probability of treatment weighting (IPTW) was used to adjust for confounding. IPTW-adjusted Poisson regression was used to evaluate the adjusted rVE of aIIV3 versus HD-IIV3e. All-cause and influenza-related healthcare resource utilization (HCRU) and costs were examined post-IPTW. Recycled predictions from generalized linear models were used to estimate adjusted costs. Adjusted analysis showed that aIIV3 (n = 798,987) was similarly effective compared to HD-IIV3e (n = 1,655,979) in preventing influenza-related hospitalizations/ER visits (rVE 3.1%; 95% CI: −2.8%; 8.6%), hospitalizations due to any cause (−0.7%; 95% CI: −1.6%; 0.3%), and any CRD-related hospitalization/ER visit (0.9%; 95% CI: 0.01%; 1.7%). Adjusted HCRU and annualized costs were also statistically insignificant between the two cohorts. The adjusted clinical and economic outcomes evaluated in this study were comparable between aIIV3 and HD-IIV3e during the 2019–2020 influenza season.

Cost-Effectiveness and Burden of Disease for Adjuvanted Quadrivalent Influenza Vaccines Compared to High-Dose Quadrivalent Influenza Vaccines in Elderly Patients in Spain

“…Four studies [28][29][30][31] were identified from the published systematic review. The remaining four studies/effect estimates [32][33][34][35] were identified via the targeted review, two of which were not yet published as of the time of the analysis. As the relative vaccine effectiveness of aTIV vs. HD-TIV may be expected to vary based on the characteristics of the study (e.g., influenza season, population included, outcome definition, etc.…”

Room for improvement in current influenza vaccines? A systematic literature review on the humanistic and economic burden of influenza in older (≥65 years old) adults

“…Fifteen studies reported the economic burden of seasonal influenza in adults aged [? ]65 years (28,34,35,(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52). The majority of studies (n=7) were conducted in the US (34,(41)(42)(43)(44)(45)(46).…”

“…]65 years (28,34,35,(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52). The majority of studies (n=7) were conducted in the US (34,(41)(42)(43)(44)(45)(46). Very few studies were conducted in other countries of interest, including Spain (n=2) (50,51), China (n=1) (47), France (n=1) (48), Germany (n=1) (49), the UK (n=1) (28), Japan (n=1) (52), and South Africa (n=1) (35).…”

Comparative effectiveness of adjuvanted versus high-dose seasonal influenza vaccines for older adults: a systematic review and meta-analysis

“…Following the removal of duplicates (n = 226), a total of 857 records were screened by title and/or abstract and 841 papers were judged clearly ineligible. Of 16 full texts evaluated, 9 (Boikos et al, 2021;Izurieta et al, 2019;Izurieta et al, 2020;Izurieta et al, 2021;Levin et al, 2021;Machado et al, 2021;Pelton et al, 2020;Pelton et al, 2021;van Aalst et al, 2020) were included in the study, while 7 were excluded with reasons (Supplementary Table S3). The updated search identified another relevant study (Imran et al, 2022).…”

“…No studies were identified through manual search. In summary, 10 peerreviewed articles (Boikos et al, 2021;Imran et al, 2022;Izurieta et al, 2019;Izurieta et al, 2020;Izurieta et al, 2021;Levin et al, 2021;Machado et al, 2021;Pelton et al, 2020;Pelton et al, 2021;van Aalst et al, 2020) underwent both qualitative and quantitative syntheses. Supplementary Figure S1 depicts the whole study selection process.…”