A clinical and economic assessment of adjuvanted trivalent versus standard egg-derived quadrivalent influenza vaccines among older adults in the United States during the 2018-19 and 2019-20 influenza seasons

ABSTRACT

Background

Clinical evidence supports use of enhanced influenza vaccines in older adults. Few economic outcome studies have compared adjuvanted trivalent inactivated (aIIV3) and standard egg-derived quadrivalent inactivated influenza vaccines (IIV4e).

Research Design and Methods

A retrospective cohort study was conducted leveraging deidentified US hospital data linked to claims data during the 2018–19 and 2019–20 influenza seasons. Relative vaccine effectiveness (rVE) was compared in adults aged ≥ 65 years receiving aIIV3 or IIV4e using inverse probability of treatment weighting (IPTW) and Poisson regression. An economic assessment quantified potential real-world cost savings.

Results

The study included 715,807 aIIV3 and 320,991 IIV4e recipients in the 2018–19 and 844,169 aIIV3 and 306,270 IIV4e recipients in the 2019–20 influenza seasons. aIIV3 was significantly more effective than IIV4e in preventing cardiorespiratory disease (2018–19 rVE = 6.2%; and 2019–20 rVE = 6.0%) and respiratory disease (2018–19 rVE = 8.9%; and 2019–20 rVE = 10.1%). During the 2018–19 influenza season cardiorespiratory hospitalization cost savings for the aIIV3 population were $392 M, and $221 M for the 2019–20 season. Respiratory hospitalization cost savings for the aIIV3 population were $145 M and $97 M, respectively.

Conclusions

Our findings suggest that aIIV3 provides clinical and economic advantages versus IIV4e in the elderly.

Plain Language Summary

Flu vaccines do not work as well in older adults due to the aging of their immune system. One approach to improving vaccine efficacy is the addition of a substance, or adjuvant, to the vaccine in order to boost an individual’s immune response. This study evaluated an adjuvanted vaccine compared to an unadjuvanted vaccine for preventing cardiorespiratory hospitalizations and hospitalization costs. The findings demonstrated that the adjuvanted flu vaccine, compared to the unadjuvanted vaccine, prevented more hospitalizations and greatly reduced associated hospital costs.

KEYWORDS:

• Adjuvanted
• aIIV3
• influenza vaccine
• economic assessment
• elderly
• relative vaccine effectiveness

Declaration of interest

V Divino, Z Zhao and M DeKoven are employees of IQVIA, which received funding for this study from Seqirus. SI Pelton, MJ Postma and M Levin received financial support for their time and effort from Seqirus for this study. J Mould-Quevedo is an employee of CSL Seqirus Inc. and a shareholder. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or material discussed in the manuscript apart from those disclosed.

Reviewer disclosures

A reviewer on this manuscript has received grant funding from Sanofi and has received funding from Merck. They serve on an advisory board for GSK. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

Conceptualization, JM, VD, MD; study design and data interpretation, JM, VD, MD, ZZ, SIP, MJP and MJL; drafting of the article, VD; critical revision of the article, SIP, JM, MD, ZZ, MJP and MJL; funding acquisition, JM. All authors have read and provided final approval of the submitted version of the manuscript. All authors attest that they meet the ICMJE criteria for authorship.

Data availability statement

The original deidentified data used in this analysis were obtained from and are the property of IQVIA. IQVIA has restrictions prohibiting the authors from making the dataset publicly available. Interested researchers may contact IQVIA to apply to gain access to this study’s data in the same way the authors obtained the data (see https://www.iqvia.com/contact/sf).

Ethics approval

Ethical review and approval were not required for the retrospective analysis of the deidentified secondary data. Informed consent was not required for this type of study.

Acknowledgments

The authors would like to thank Lia Pizzicato, Senior Consultant at IQVIA, for medical writing assistance in the preparation of this paper.

Geolocation information

United States

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/14760584.2023.2293237.

Additional information

Funding

This study was funded by CSL Seqirus Inc.