Epidemic Intelligence from Open Sources (EIOS) is the world’s leading initiative for open-source intelligence for public health decision-making. It is led by the WHO as part of its constitutional mandate as the directing and coordinating authority on international health work. EIOS is built on three pillars: a growing global community of practice, a range of multi-disciplinary collaborators and an evolving fit-for-purpose system. The system builds on a long-standing collaboration between WHO and the Joint Research Centre (JRC) of the European Commission (EC).