Relative Effectiveness of the Cell-Based Quadrivalent Influenza Vaccine in Preventing Cardiorespiratory Hospitalizations in Adults Aged 18-64 Years During the 2019-2020 US Influenza Season

Mahrukh Imran; Juan Puig-Barbera; Justin R Ortiz; Lorena Lopez-Gonzalez; Alex Dean; Machaon Bonafede; Mendel Haag

doi:10.1093/ofid/ofad304

Relative Effectiveness of the Cell-Based Quadrivalent Influenza Vaccine in Preventing Cardiorespiratory Hospitalizations in Adults Aged 18-64 Years During the 2019-2020 US Influenza Season

Open Forum Infect Dis. 2023 Jun 7;10(7):ofad304. doi: 10.1093/ofid/ofad304. eCollection 2023 Jul.

Authors

Mahrukh Imran¹, Juan Puig-Barbera², Justin R Ortiz³, Lorena Lopez-Gonzalez⁴, Alex Dean⁴, Machaon Bonafede⁴, Mendel Haag⁵

Affiliations

¹ CSL Seqirus, Kirkland, Quebec, Canada.
² FISABIO, Valencia, Spain.
³ University of Maryland School of Medicine, Baltimore, Maryland, USA.
⁴ Veradigm, Chicago, Illinois, USA.
⁵ CSL Seqirus Netherlands B.V., Amsterdam, the Netherlands.

Abstract

Background: The mammalian cell-based quadrivalent inactivated influenza vaccine (IIV4c) has advantages over egg-based quadrivalent inactivated influenza vaccine (IIV4e), as production using cell-derived candidate viruses eliminates the opportunity for egg adaptation. This study estimated the relative vaccine effectiveness (rVE) of IIV4c versus IIV4e in preventing cardiorespiratory hospitalizations during the 2019-2020 US influenza season.

Methods: We conducted a retrospective cohort study using electronic medical records linked to claims data of US individuals aged 18-64 years. We assessed rVE against cardiorespiratory hospitalizations and against subcategories of this outcome, including influenza, pneumonia, myocardial infarction and ischemic stroke, and respiratory hospitalizations. We used a doubly robust inverse probability of treatment weighting and logistic regression model to obtain odds ratios (ORs; odds of outcome among IIV4c recipients/odds of outcome among IIV4e recipients) adjusted for age, sex, race, ethnicity, geographic region, vaccination week, health status, frailty, and healthcare resource utilization. rVE was calculated as 100(1 - OR_adjusted).

Results: In total, 1 491 097 individuals (25.2%) received IIV4c, and 4 414 758 (74.8%) received IIV4e. IIV4c was associated with lower odds of cardiorespiratory (rVE, 2.5% [95% confidence interval, 0.9%-4.1%]), respiratory (3.7% [1.5%-5.8%]), and influenza (9.3% [0.4%-17.3%]) hospitalizations among adults 18-64 years of age. No difference was observed for the other outcomes.

Conclusions: This real-world study conducted for the 2019-2020 season demonstrated that vaccination with IIV4c was associated with fewer cardiorespiratory, respiratory, and influenza hospitalizations compared with IIV4e.

Keywords: cardiovascular-respiratory illness; cell-based quadrivalent influenza vaccine; hospitalizations; real-world evidence; relative vaccine effectiveness.