Beyond vaccine hesitancy: Vaccine fatigue and sustained engagement with vaccination

Objective: To explore vaccine fatigue as a potentially important psychological state which can affect sustained engagement and adherence with vaccination. Methods: This commentary integrates emerging vaccine fatigue literature with established behavioural science literature on message fatigue, information overload, and information avoidance. Results: We propose vaccine fatigue as a potential dynamic psychological state of exhaustion and declining motivation to continue engaging with vaccination decisions, including for individuals broadly supportive of vaccines. The model separates antecedents, including decision and information burden, from the construct of fatigue and from downstream behaviours such as avoidance, postponement, and reduction in uptake. Vaccine fatigue is positioned as complementary to, rather than synonymous with, vaccine hesitancy, and criteria are set out for distinguishing it from declining perceived benefit and from system-level changes in vaccine access. Conclusions: Examining vaccine fatigue as a construct, with its own research agenda and measurement approaches, could improve understanding and tailoring of interventions that sustain engagement with vaccination.