Vaccine hesitancy is widely defined as delayed acceptance of vaccines or refusing to vaccinate despite vaccination services being offered. It is a burning issue for healthcare professionals who meet more and more challenges in building trust relationships with their patients. The EU-funded VAX-TRUST project will explore vaccine hesitancy as a societal phenomenon and help healthcare professionals to deal with it in Europe. Specifically, VAX-TRUST will equip healthcare professionals with tailored up-to-date knowledge on vaccine hesitancy in their specific local region and nation with an international perspective. The project will conduct quantitative and qualitative studies including interviews with healthcare professionals and vaccine hesitant individuals. VAX-TRUST takes into account that some professionals may themselves be vaccine hesitant.