Abstract Removing barriers in the health system that make it difficult for cultural, religious or ethnic minorities to access vaccinations is an urgent concern in order to prevent infectious diseases in the future. Childhood vaccine uptake for MMR and HPV in most underserved communities is lower than in the general population. The project RIVER-EU (Reducing Inequalities in Vaccine uptake in the European region - Engaging Underserved communities) engages the migrant community in Greece, females with a Turkish or Moroccan migration background in the Netherlands, the Ukrainian minority in Poland and marginalized Roma communities in Slovakia to remove health system barriers to vaccination. Barriers include, e.g., lack of culturally and linguistically appropriate information, financial barriers, insufficient capacities, coordination and delivery of health care. Based on a Participatory Action Research (PAR) approach we selected and adapted potentially transferable evidence-based interventions in partnership with the communities. First, we pre-selected 6 useful interventions from a realist review on 36 effective vaccine uptake interventions. Second, we assessed them in depth for their transferability. Building a bridge between evidence on interventions and community needs is not an easy task: We involved various stakeholders in a longitudinal process under consideration of contextual conditions in the primary intervention context and the context of the respective underserved community. We co-created knowledge through 25 workshops and 39 interviews or focus groups for decision-making and determining need for adaptation of selected interventions. The aim of this workshop is to present the results of this co-creative process in each country. Special attention is payed to facilitators and barriers for transferability of evidence-based interventions from the perspective of underserved communities, and contextual commonalities and differences that lead to a specific intervention tailoring. This workshop will contribute to an improved understanding of how to consider contextual needs underserved communities have to remove health system barriers to vaccination on the one hand and suitable evidence on interventions to improve their situation on the other hand. The workshop will include five presentations of eight minutes and a questions and answers session to involve the audience. First, an introductory presentation on transferability of interventions for HPV and MMR vaccine uptake to underserved communities in specific contexts will be given. Then each country will present the intervention(s) to address health system barriers adapted to their context. Thereby, we will underline common key elements that have potential for transferability in all countries. After all presentations, we will discuss the need for context-based decision-making on evidence-based interventions and intervention tailoring to improve vaccine uptake for cultural, religious or ethnic minorities. Key messages • Improving vaccine uptake in underserved communities requires local solutions with tailored interventions. Trusted partnerships with various stakeholders are key to reducing health system barriers. • Participatory approaches to evidence-informed decision-making build bridges between evidence on interventions and needs of underserved communities to understand the transferability of interventions.