Mapping and ranking outcomes for the evaluation of seasonal influenza vaccine efficacy and effectiveness: a delphi study
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Published on: July 26, 2019
Chiara de Waure1, Elisabetta Alti2, Vincenzo Baldo3
1Department of Medicine and Surgery, University of Perugia, Perugia, Italy.
Background:
Protection provided by seasonal influenza vaccination (SIV) may be measured against numerous outcomes, and their heterogeneity may hamper decision-making. The aim of this study was to explore outcomes used for estimation of SIV efficacy/effectiveness (VE) and obtain expert consensus on their importance.
Research Design And Methods:
An umbrella review was first conducted to collect and map outcomes considered in systematic reviews of SIV VE. A Delphi study was then performed to reach expert convergence on the importance of single outcomes, measured on a 9-point Likert scale, in principal target groups, namely children, working-age adults, older adults, subjects with co-morbidities and pregnant women.
Results:
The literature review identified 489 outcomes. Following data reduction, 20 outcomes were selected for the Delphi process. After two Delphi rounds and a final consensus meeting, convergence was reached. All 20 outcomes were judged to be important or critically important. More severe outcomes, such as influenza-related hospital encounters and mortality with or without laboratory confirmation, were generally top-ranked across all target groups (median scores ≥8 out of 9).
Conclusions:
Rather than focusing on laboratory-confirmed infection per se, experimental and observational VE studies should include more severe influenza-related outcomes because they are expected to exercise a greater impact on decision-making.
