A real-world study evaluating the relative vaccine effectiveness of a cell-based quadrivalent influenza vaccine compared to egg-based quadrivalent influenza vaccine in the US during the 2017–18 influenza season. Issue 40 (11th September 2020)

• Record Type: Journal Article
• Authors: Divino, Victoria; Krishnarajah, Girishanthy; Pelton, Stephen I.; Mould-Quevedo, Joaquin; Anupindi, Vamshi Ruthwik; DeKoven, Mitch; Postma, Maarten J.
• Is Part Of: Vaccine. Volume 38:Issue 40(2020)
• Page Start: 6334
• Page End: 6343
• Publication Date: 2020-09-11
• Subjects: Influenza -- Influenza vaccine -- Relative vaccine effectiveness -- Retrospective studies -- Observational studies -- Cell-based influenza vaccine; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2020.07.023
• Languages: English
• ISSNs: 0264-410X

Abstract

Abstract: Background: Cell-based influenza vaccine manufacturing reduces egg adaptations that can decrease vaccine effectiveness. We evaluated the relative vaccine effectiveness (rVE) of cell-based quadrivalent influenza vaccine (QIVc) compared to standard-dose egg-based quadrivalent influenza vaccines (QIVe-SD) against influenza-related and serious respiratory events among subjects 4–64 years of age during the 2017–18 influenza season. Methods: A retrospective cohort analysis was conducted using administrative claims data in the US (IQVIA PharMetrics Plus® database). Subjects vaccinated with QIVc or QIVe-SD from 8/2017–1/2018 were identified (date of vaccination termed the index date). Influenza-related hospitalizations/ER visits, all-cause hospitalizations and serious respiratory hospitalizations/ER visits were assessed post-vaccination. Inverse probability of treatment weighting (IPTW) and Poisson regression were used to evaluate the adjusted rVE of QIVc compared to QIVe-SD. In a subgroup analysis, rVE was assessed for several subgroups of interest (4–17, 18–64 and 50–64 years, and subjects with ≥1 high-risk condition). In a secondary economic analysis, annualized all-cause costs over the follow-up were compared using propensity score matching (PSM) and generalized estimating equation (GEE) models. Results: The study sample comprised 555, 538 QIVc recipients and 2, 528, 524 QIVe-SD recipients. Prior to adjustment, QIVc subjects were older and had higher total costs in the 6-months pre-index. Following IPTW-adjustment and Poisson regression, QIVc was more effective in reducing influenza-related hospitalizations/ER visits, all-cause hospitalizations, and hospitalizations/ER visits related to asthma/COPD/bronchial events and other respiratory events compared to QIVe-SD. Similar trends were generally observed in the subgroup analysis. Following PSM adjustment and GEE regression, QIVe-SD was associated with significantly higher annualized all-cause total costs compared to QIVc, driven by higher costs for outpatient medical services and inpatient hospitalizations. Conclusions: After adjustment for confounders and selection bias, QIVc reduced influenza-related hospitalizations/ER visits, all-cause hospitalizations, and serious respiratory hospitalizations/ER visits compared to QIVe-SD. QIVc was associated with significantly lower all-cause total costs.