Barriers of Influenza Vaccination Intention and Behavior - A Systematic Review of Influenza Vaccine Hesitancy, 2005 - 2016

Abstract

Background: Influenza vaccine hesitancy is a significant threat to global efforts to reduce the burden of seasonal and pandemic influenza. Potential barriers of influenza vaccination need to be identified to inform interventions to raise awareness, influenza vaccine acceptance and uptake.

Objective: This review aims to (1) identify relevant studies and extract individual barriers of seasonal and pandemic influenza vaccination for risk groups and the general public; and (2) map knowledge gaps in understanding influenza vaccine hesitancy to derive directions for further research and inform interventions in this area.

Methods: Thirteen databases covering the areas of Medicine, Bioscience, Psychology, Sociology and Public Health were searched for peer-reviewed articles published between the years 2005 and 2016. Following the PRISMA approach, 470 articles were selected and analyzed for significant barriers to influenza vaccine uptake or intention. The barriers for different risk groups and flu types were clustered according to a conceptual framework based on the Theory of Planned Behavior and discussed using the 4C model of reasons for non-vaccination.

Results: Most studies were conducted in the American and European region. Health care personnel (HCP) and the general public were the most studied populations, while parental decisions for children at high risk were under-represented. This study also identifies understudied concepts. A lack of confidence, inconvenience, calculation and complacency were identified to different extents as barriers to influenza vaccine uptake in risk groups.

Conclusion: Many different psychological, contextual, sociodemographic and physical barriers that are specific to certain risk groups were identified. While most sociodemographic and physical variables may be significantly related to influenza vaccine hesitancy, they cannot be used to explain its emergence or intensity. Psychological determinants were meaningfully related to uptake and should therefore be measured in a valid and comparable way. A compendium of measurements for future use is suggested as supporting information.

Fig 1. Micro-level determinants of vaccine hesitancy following an extended version of the Theory of Planned Behavior (TPB).

Determinants are based on empirical and theoretical work from Ajzen [23], Schmiege et al. [25], Rhodes & Courneya [26], Koo et al. [27], Pomery et al. [28], Larson et al. [10]. Significant determinants from 470 research articles are clustered according to the model. Circle size represents the total number of reported incidents.

Fig 2. Flow Chart of selection process.

Fig 3. Total number of multivariate studies about influenza vaccine hesitancy by year of publication (2005–2015) and region (N = 470).

Fig 4. Barriers to influenza vaccine uptake mapped onto the macro-level 4C model of vaccine hesitancy (complacency, convenience, confidence and calculation).

Total numbers of studies reporting the variable as either decreasing (white) or increasing (black) vaccine acceptance or inconclusive (circled number).

Fig 5. Barriers to seasonal and pandemic influenza vaccine uptake for each risk group aggregated using the macro-level 4C model of vaccine hesitancy (complacency, convenience, confidence and calculation).

Bars visualize the total number of significant results supporting each reason for hesitancy for each risk group. Grey bars indicate the absolute proportion of results addressing pandemic influenza uptake among the total results. Black bars indicate the absolute proportion of results for seasonal influenza uptake among the total results.