Background and Objective: Adult vaccinations are a core pillar of any preventive health strategy. Nevertheless, adults have far fewer vaccinations recommended in the schedule with respect to other age groups, as well as reduced funding, few registries for tracking and recall and fewer incentives. In the European context, the adult vaccination plans are not homogeneous and an increasing number of countries show very different vaccination coverage rates. Starting from these premises, the present systematic review analyzes existing strategies and policies used for adult vaccination of seven countries of the European region, emphasizing weaknesses and strengths of immunization schedules. Methods: Selected countries were Germany, France, UK, Italy and Spain plus Sweden, as an example of a country implementing recognized best practices for vaccination, and Romania, for its difficulties due to widespread vaccine hesitancy. Three main scientific databases (PubMed, Scopus and web of science) were queried and the PRISMA guidelines were followed. Studies assessing weaknesses or strengths factors, facilitators and barriers related to the adult vaccination plans were considered eligible. Quality assessment of included studies was also conducted. Results: We included ten studies with a medium/high score at the quality assessment. Main barriers and strength factors for vaccination can be divided into the following categories: financial aspects (e.g. If the vaccine has a funding mechanism); administrative/practical factors (e.g. Complex booking systems); geographical factors (e.g. Geographical proximity, places of vaccination); factors related to healthcare professionals (e.g. Availability of trained staff); factors related to vaccine supply. Conclusions: Substantial improvement in adult vaccination uptake is urgently necessary in order to decrease the burden of infectious disease on healthcare systems. In order to achieve this goal, vaccination strategies and policies should leverage on the existing facilitators of immunization plans and try to remove local barriers to vaccine uptake.