The main objective of VAX-ACTION is to support EU Member States and relevant stakeholders to implement a combination of tailored, evidence-based interventions aimed to reduce vaccine hesitancy. The combination will be based on evaluation of effectiveness of interventions that build on the existing evidence. Attending to the objectives of the call, interventions will be conducted with selected target regions in 5 EU member states (Portugal, Italy, France, Romania, and Czechia). The recommendations for embedding improvement and change will be prioritised along with tailored dissemination and evaluation strategies. This will support scale up and translation to other member states, WHO European Region members and other countries where there have been gaps in implementation of evidence-based action to address vaccine hesitancy. The key relevance of VAX-ACTION to the scope of this call is that our interventions and recommendations build on sound theory, existing evidence, and best practice in application of evaluation. We use a co-design model to engage Frontline Healthcare Workers (FHWs), specific population groups (e.g., newly arrived migrants, hesitant parents, people of low socio-economic status) to tailor interventions to their requirements and the specific issues raised by recently approved vaccines for emergent diseases/infections/virus such as Covid-19 and mpox, mass vaccination and loss of trust in long-standing vaccines included in national vaccination programmes.