EpiSUS 25 years: an experience report on advances and legacies in field epidemiology and public health surveillance in Brazil, 2000-2025.

To describe the experience of implementing the Field Epidemiology Training Program for the Brazilian National Health System (Programa de Treinamento em Epidemiologia Aplicada aos Serviços do Sistema Único de Saúde - EpiSUS), highlighting key milestones, progress and challenges, and future perspectives for strengthening health surveillance and emergency response in Brazil. Methods: This was an experience report based on technical documents, institutional publications of the Program, and key informants. Results: EpiSUS was implemented in 2000 with international support and became fully nationalized in 2009. In 2017, the pyramid model began to expand in the country starting from the basic level. Two years later, activities at the intermediate level began, in partnership with the Oswaldo Cruz Foundation, Brasília unit. By early 2025, more than 4,000 professionals had been trained in field epidemiology across the three levels of EpiSUS, most of them at the basic level (3,533), followed by the intermediate (778) and advanced levels (196). Conclusion: The outcomes monitored over the years reflect the efforts of management teams and trainees in responding to public health emergencies at the national, state/district, and municipal levels. The implementation of the basic and intermediate levels brought innovations to the training approach. The outputs produced by trainees provide diverse inputs to support timely and evidence-based decision-making.