Adjuvanted versus non-adjuvanted standard-dose influenza vaccines in preventing all-cause hospitalizations in the elderly: a cohort study with nested case-control analyses over 18 influenza seasons. (2nd November 2022)

• Record Type: Journal Article
• Authors: Lapi, Francesco; Domnich, Alexander; Marconi, Ettore; Rossi, Alessandro; Cricelli, Claudio
• Is Part Of: Expert review of vaccines. Volume 21:Number 11(2022)
• Page Start: 1647
• Page End: 1653
• Publication Date: 2022-11-02
• Subjects: Influenza vaccine -- older adults -- all-cause hospitalization -- primary care -- nested Case-Control studies; Vaccines -- Periodicals; Vaccination -- Periodicals; 615.37205
• DOI: 10.1080/14760584.2022.2115362
• Languages: English
• ISSNs: 1476-0584

Abstract

ABSTRACT: Background: The higher effectiveness of adjuvanted trivalent influenza vaccine (aTIV) versus non-adjuvanted (na) formulations in preventing all-cause hospitalization has been demonstrated for a single influenza season and in institutionalized elderly only. This study evaluated the relative vaccine effectiveness for aTIV vs. non-adjuvanted trivalent (naTIV) and/or quadrivalent (naQIV) influenza vaccines in preventing all-cause hospitalizations across 18 influenza seasons in primary care. Research design and methods: Using Health Search Database, a nested case-control analysis was conducted in a cohort of older adults being vaccinated with aTIV or naTIV/naQIV. Conditional logistic regression was adopted to estimate the odds ratio (OR) of all-cause hospitalizations occurred during the epidemic period. Results: Of 58, 252 patients vaccinated with aTIV and naTIV/naQIV for the first time, 2, 504 cases of all-cause hospitalization (3.46 per 1, 000 person-weeks) during the 18 influenza seasons were identified. Compared with naTIV/naQIV, aTIV was associated with a 12% reduced the odds of all-cause hospitalizations (OR 0.88; 95% CI: 0.80–0.97). Conclusions: In an 18-season cohort of older adults, aTIV reduced the risk of all-cause hospitalizations when compared with naTIV/naQIV. Our findings confirm additional benefits for adjuvanted influenza vaccines in older adults.