In response to the pressing need to improve epidemic preparedness, this paper presents the development and application of EPISOS, a project designed to improve the timeliness, completeness, and accessibility of epidemiological data. Through EPISOS, we have created a dynamic, cross-sectoral collaborative framework that supports the detection, monitoring, and risk assessment of emerging and re-emerging infectious diseases across Europe. This initiative not only addresses the challenges of standardizing data quality and resource availability, but also promotes equity in data access and use. The paper critically analyzes the difficulties encountered in these areas and outlines effective strategies for leveraging open science to strengthen public health responses. Integrating real-world examples, we illustrate the practical impact and potential of EPISOS in promoting scientific collaboration and transparency during health crises.