The Essential Programme for Immunization (EPI) is a core unit within IVB responsible for supporting countries to strengthen immunization systems and deliver high-quality, equitable vaccination services across the life course. The unit provides technical leadership, normative guidance, and operational support to improve routine immunization performance, introduce new vaccines, and build resilient immunization programmes aligned with primary health care and universal health coverage objectives. 

EPI comprises three main teams: Immunization Programme Strengthening (IPS), Demand and Innovations (DIN), and Accelerated Disease Control and Elimination (ADC). Together, these teams work on routine immunization strengthening, vaccine demand and community engagement, supply chain and service delivery innovations, outbreak preparedness and response, disease elimination initiatives, and integration of immunization with broader health services. 

Key strategic priorities include reaching under-immunized and zero-dose populations, improving immunization coverage and equity, strengthening country capacity and health systems, supporting the introduction of priority vaccines, and accelerating progress towards disease control, elimination, and eradication goals. The unit also works closely with countries, regions, Gavi, UNICEF, and other partners to advance sustainable immunization programmes and strengthen monitoring, accountability, and programme performance. 

Through its technical expertise, country support, and normative leadership, EPI contributes directly to IVB's mission of reducing vaccine-preventable diseases and to WHO's broader goals of promoting health, preventing illness, and achieving equitable access to life-saving immunization services worldwide.