AbstractObjectivesTo specify future intervention content to enhance influenza vaccination uptake using the Behaviour Change Wheel (BCW).DesignCross-sectional, multi-modal data collection and subsequent behaviourally informed analysis and expert stakeholder engagement.MethodsContent analysis was initially used to identify barriers and enablers to influenza vaccination from nine semi-structured focus groups, 21 individual interviews and 101 open-ended survey responses. Subsequently, the Theoretical Domains Framework (TDF) and the BCW were used to specify evidence-based and theoretically-informed future intervention content in the form of preliminary recommendations. Finally, drawing on the APEASE criteria, expert stakeholders refined our recommendations to yield a range of multi-levelled potentially actionable ideas.ResultsThe TDF domain of ‘Beliefs about Consequences’ was the most frequently mapped domain with themes relating to ‘perceptions of side effects (barrier)’ and ‘feeling protected from catching flu (enabler)’. The next most important domain was ‘Environmental Context and Resources’ with themes relating to ‘time constraints (barrier)’ and ‘receiving reminders to vaccinate (enabler)’. Next, ‘Social Influences’ was identified with themes relating to ‘encouragement from others (enabler)’, followed by ‘Emotion’ with themes relating to ‘fear of needles (barrier)’. These factors mapped to seven of the nine intervention functions and 22 identified behaviour change techniques (BCTs). Stakeholders reduced an initial 26 recommendations to 21.ConclusionsOur comprehensive analyses showed that the factors affecting vaccine uptake were multifaceted and multileveled. The study suggested a suite of complementary multi-level intervention components may usefully be combined to enhance vaccination uptake involving a range of diverse actors, intervention recipients and settings.Statement of ContributionWhat is already known on this subject?Uptake of the influenza vaccination in those with an “at-risk” health condition is low and has been decreasing year on year.The reasons for vaccine hesitancy are complex and involve psychological, social and contextual factors.There is a lack of theory-based intervention content aimed at increasing influenza vaccination uptake.What does this study add?This study showed that the factors affecting vaccine uptake were multifaceted and multileveled. They could be theorised as relating to the TDF domains of ‘Beliefs about Consequences’, ‘Environmental Context and Resources’, ‘Social Influences’ and ‘Emotion’.With the help of key stakeholders the study suggested a suite of complementary multi-level intervention components may be most useful to enhance vaccination compliance involving a range of diverse actors, intervention recipients and settings.Mass and social media interventions, and interactions between recipients and healthcare providers should include clear and concise information about vaccine side-effects and directly address misinformation. Community-based vaccination delivery methods should be enhanced by modifying traditional and adopting novel approaches.