[Brazil's Unified Health System: history and challenges]

Established in 1988, the Unified Health System (SUS) unified the public system by transferring social security resources to states and municipalities. Its principles are universal access, fiscal financing, decentralization, and regional organization guided by primary health care. Financing is the responsibility of the three levels of government, with increasing municipal participation. Total health expenditure is 9.8% of GDP, with 44% public, 29% from private insurance, and 22% out-of-pocket spending. Underfunding has been an obstacle since SUS's creation, as public spending being lower than private constitutes a barrier to the principle of universal access. Governance proposes collegial decision-making between government levels and social participation, but in practice management is still fragmented, influenced by political-party interests and high turnover of managers, making it difficult the build of integrated networks. Nevertheless, the expansion of primary health care through the Family Health Strategy in 5570 municipalities, with 53,000 teams and 280,000 community agents, has had positive impacts. The current agenda of regionalization and expansion of specialized care aims to reduce waiting times, strengthen system legitimacy, and could promote its reconstruction from the ground up. Integrated public-private regulation and structural limits on social spending remain persistent challenges.