Relative vaccine efficacy of high-dose versus standard-dose influenza vaccines in preventing probable influenza in a Medicare Fee-for-Service population. Issue 29 (15th June 2020)

• Record Type: Journal Article
• Authors: Paudel, Misti; Mahmud, Salah; Buikema, Ami; Korrer, Stephanie; Van Voorhis, Damon; Brekke, Lee; Chit, Ayman
• Is Part Of: Vaccine. Volume 38:Issue 29(2020)
• Page Start: 4548
• Page End: 4556
• Publication Date: 2020-06-15
• Subjects: Aged -- Cohort studies -- Influenza, human -- Influenza vaccines -- Vaccine effectiveness; CMS Centers for Medicare and Medicaid Services -- CPT Current Procedural Terminology -- FFS fee-for-service -- HD high-dose -- ICD-9-CM International Classification of Diseases, 9th Edition, Clinical Modification -- NPI National Provider Index -- P&I pneumonia and influenza -- RCT randomized controlled trial -- rVE relative vaccine effectiveness -- SD standard-dose -- SMD standardized mean difference; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2020.05.020
• Languages: English
• ISSNs: 0264-410X

Abstract

Highlights: We evaluated the relative effectiveness of influenza vaccines among US seniors. High-dose vaccine was more effective than standard-dose across multiple seasons. These real-world findings align with data from randomized controlled trials. Our study shows the utility of claims data in comparative effectiveness research. Abstract: Background: High-dose (HD) influenza vaccine, currently the most commonly used vaccine among US seniors (aged ≥ 65 years), has been shown to be more efficacious than standard-dose (SD) vaccine in multiple randomized trials. This study evaluated the real-world relative vaccine effectiveness (rVE) of HD vs SD over four influenza seasons. Methods: This study included Medicare Fee-for-Service enrollees who received HD or SD at an outpatient clinic or pharmacy during influenza seasons 2011–2012 through 2014–2015. Probable influenza (an inpatient stay with an influenza diagnosis on the claim, or an outpatient visit with a rapid influenza test/culture followed by an antiviral prescription) was assessed among HD recipients matched 1:1 with SD recipients by location, vaccination date, age, and sex. Fine-Gray subdistribution hazard models with competing risk of death were used to adjust for residual confounding. Analyses were stratified by outpatient vs pharmacy vaccination. Results: Across the four influenza seasons, there were 535, 598, 1, 017, 552, 1, 548, 164, and 2, 420, 450 in the pharmacy cohort; and 821, 662, 1, 151, 080, 1, 559, 488, and 2, 421, 758 in the outpatient cohort. During peak influenza season, rVEs for 2011–12 through 2014–15 were 21.8% (95% CI: −5.9%, 42.3%), 14.8% (9.3%, 19.9%), 16.9% (9.2%, 23.9%), and 17.2% (14.5%, 19.9%), respectively, in the pharmacy cohort; and 16.5% (−5.9%, 34.2%), 15.1% (10.9%, 19.1%), 10.0% (2.9%, 16.6%), and −0.2% (−3.0%, 2.5%), respectively, in the outpatient cohort. Conclusion: HD was consistently associated with better protection against probable influenza. The lower treatment effect observed in the outpatient cohort could reflect provider bias due to physicians triaging HD to frailer patients.