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

• Published in: Vaccine Vol. 38; no. 40; pp. 6334 - 6343
• Main Authors: Divino, Victoria, Krishnarajah, Girishanthy, Pelton, Stephen I., Mould-Quevedo, Joaquin, Anupindi, Vamshi Ruthwik, DeKoven, Mitch, Postma, Maarten J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 11.09.2020; Elsevier Limited
• Subjects: Adaptation; Age; Allergy and Immunology; Asthma; Cell culture; Cell-based influenza vaccine; Childrens health insurance programs; Chronic obstructive pulmonary disease; Cost analysis; Demographics; Disease; Drug dosages; Economic analysis; Eggs; equations; Evaluation; Gender; Health insurance; Hospitalization; Humans; Influenza; Influenza vaccine; Influenza Vaccines; Influenza, Human - prevention & control; Medicare; Mutation; Observational studies; Pharmacy; Poisson density functions; Population; probability; Regression analysis; Relative vaccine effectiveness; Retrospective Studies; Seasons; Statistical analysis; Subgroups; Vaccination; Vaccine efficacy; Vaccines; Viruses; United States > US; Cell-based influenza vaccine; Retrospective studies; Influenza vaccine; Observational studies; Influenza; Relative vaccine effectiveness
• DOI: 10.1016/j.vaccine.2020.07.023
• ISSN: 0264-410X; 1873-2518

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. 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. 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. 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.