Analysis of relative effectiveness of high-dose versus standard-dose influenza vaccines using an instrumental variable method

AbstractInfluenza immunization protects seniors against influenza and its potentially serious complications. It is uncertain whether standard-dose (SD) quadrivalent vaccine offers better protection over other formulations in the elderly. In this study, we compared the effectiveness of SD-trivalent, high-dose (HD) trivalent, SD-quadrivalent, and adjuvanted trivalent vaccines in seniors (≥65 years) in a real-world setting. We selected over 200,000 individuals in each of 6 influenza seasons from 2012 to 2018 using MarketScan® databases. The two outcomes were hospitalization or emergency room (ER) visit due to (1) influenza or (2) pneumonia. Here, SD-quadrivalent was associated with higher risk of influenza-related hospitalization/ER visit (adjusted hazard ratio (aHR) 1.14 and 95% confidence interval (95% CI) 1.05–1.24) and of pneumonia-related hospitalization/ER visit (aHR 1.04 and 95% CI 1.01–1.07) vs. HD-trivalent. SD-trivalent followed similar trends compared to HD-trivalent (aHR 1.16 and 95% CI 1.06–1.27 for hospitalized/ER visit influenza; aHR 1.07 and 95% CI 1.05–1.10 for hospitalized/ER visit pneumonia). We could not demonstrate risk differences between SD vaccine formulations and between adjuvanted trivalent and one of the other three vaccines. Risk estimates slightly varied across seasons. These findings suggest that SD vaccine formulations vs. HD-trivalent were associated with higher risk of hospitalization/ER visit for influenza and pneumonia in seniors.

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Effect of Age on Relative Effectiveness of High-Dose Versus Standard-Dose Influenza Vaccines Among US Medicare Beneficiaries Aged ≥65 Years

The Journal of Infectious Diseases ◽

10.1093/infdis/jiz360 ◽

2019 ◽

Vol 220 (9) ◽

pp. 1511-1520 ◽

Cited By ~ 6

Author(s):

Yun Lu ◽

Yoganand Chillarige ◽

Hector S Izurieta ◽

Yuqin Wei ◽

Wenjie Xu ◽

...

Keyword(s):

Standard Dose ◽

Relative Effectiveness ◽

Emergency Department Visits ◽

Influenza Vaccines ◽

High Dose ◽

Medicare Beneficiaries ◽

Poisson Models ◽

Effect Of Age ◽

Pharmacy Setting ◽

Dose Vaccine

AbstractBackgroundStudies have found that the high-dose influenza vaccine has a higher relative vaccine effectiveness (RVE) versus standard-dose vaccines in some seasons. We evaluated the effect of age on the RVE of high-dose versus standard-dose influenza vaccines among Medicare beneficiaries.MethodsA 6-season retrospective cohort study from 2012 to 2018 among Medicare beneficiaries aged ≥65 years was performed. Poisson regression was used to evaluate the effect of age on the RVE of high-dose versus standard-dose influenza vaccines in preventing influenza-related hospitalizations.ResultsThe study included >19 million vaccinated beneficiaries in a community pharmacy setting. The Poisson models indicated a slightly increasing trend in RVE with age in all seasons. The high-dose vaccine was more effective than standard-dose vaccines in preventing influenza-related hospital encounters (ie, influenza-related inpatient stays and emergency department visits) in the 2012–2013 (RVE, 23.1%; 95% confidence interval [CI], 17.6%–28.3%), 2013–2014 (RVE, 15.3%; 95% CI, 7.8%–22.3%), 2014–2015 (RVE, 8.9%; 95% CI, 5.6%–12.1%), and 2016–2017 (RVE, 12.6%; 95% CI, 6.3%–18.4%) seasons and was at least as effective in all other seasons. We also found that the high-dose vaccine was consistently more effective than standard-dose vaccines across all seasons for people aged ≥85 years. Similar trends were observed for influenza-related inpatient stays.ConclusionsThe RVE of high-dose versus standard-dose influenza vaccines increases with age.

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Relative Effectiveness of Influenza Vaccines Among the United States Elderly, 2018–2019

The Journal of Infectious Diseases ◽

10.1093/infdis/jiaa080 ◽

2020 ◽

Vol 222 (2) ◽

pp. 278-287 ◽

Cited By ~ 4

Author(s):

Hector S Izurieta ◽

Yoganand Chillarige ◽

Jeffrey Kelman ◽

Yuqin Wei ◽

Yun Lu ◽

...

Keyword(s):

Standard Dose ◽

Relative Effectiveness ◽

The Elderly ◽

The United States ◽

Influenza Vaccines ◽

Quadrivalent Vaccine ◽

High Dose ◽

Medicare Beneficiaries ◽

Inverse Probability ◽

Quadrivalent Vaccines

Abstract Background Studies among individuals ages ≥65 years have found a moderately higher relative vaccine effectiveness (RVE) for the high-dose (HD) influenza vaccine compared with standard-dose (SD) products for most seasons. Studies during the A(H3N2)-dominated 2017–2018 season showed slightly higher RVE for the cell-cultured vaccine compared with SD egg-based vaccines. We investigated the RVE of influenza vaccines among Medicare beneficiaries ages ≥65 years during the 2018–2019 season. Methods This is a retrospective cohort study using inverse probability of treatment weighting and Poisson regression to evaluate RVE in preventing influenza hospital encounters. Results Among 12 777 214 beneficiaries, the egg-based adjuvanted (RVE, 7.7%; 95% confidence interval [CI], 3.9%–11.4%) and HD (RVE, 4.9%; 95% CI, 1.7%–8.1%) vaccines were marginally more effective than the egg-based quadrivalent vaccines. The cell-cultured quadrivalent vaccine was not significantly more effective than the egg-based quadrivalent vaccine (RVE, 2.5%; 95% CI, −2.4% to 7.3%). Conclusions We did not find major effectiveness differences between licensed vaccines used among the elderly during the 2018–2019 season. Consistent with prior research, we found that the egg-based adjuvanted and HD vaccines were slightly more effective than the egg-based quadrivalent vaccines.

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