Hydrological disasters and health losses: an index-based analysis for Brazil

OBJECTIVE: To develop and apply composite indices to assess immediate losses caused by hydrological disasters in Brazil between 2000 and 2023, with a focus on human losses and damages to health infrastructure. METHODS: Data were obtained from the Integrated Disaster Information System, which consolidates national records of hydrological disasters. Seven indicators were selected for the Human Loss Index and four for the Health Infrastructure Loss Index. Indicators were normalized using Min-Max procedures and weighted through a combined Analytic Hierarchy Process and entropy method. The General Severity Index was calculated as the arithmetic mean of Human Loss Index and Health Infrastructure Loss Index, stratified into four levels of severity. Spatial and temporal analyses were conducted to identify critical regions and municipalities. RESULTS: The findings reveal significant heterogeneity in disaster impacts across time and space. Human losses exhibited greater variability than health infrastructure losses, with notable peaks in 2006, 2011, 2015, and 2019. Infrastructure damages were less frequent but highly disruptive, especially in 2012, 2019, and 2023. Municipalities in the Amazon region, particularly Japurá and Atalaia do Norte, registered the highest combined indices, reflecting compounded vulnerabilities from geographic isolation, fragile infrastructure, and socioeconomic inequalities. High General Severity Index scores were concentrated in the North, while human losses were more widely distributed, including along the densely populated southeastern coast. Results confirm that small and socioeconomically vulnerable municipalities are disproportionately affected, with limited institutional capacity to respond. CONCLUSIONS: Hydrological disasters in Brazil are strongly mediated by social inequalities, deficient urban planning, and weak preventive policies. Human and infrastructure losses disproportionately affect vulnerable populations, particularly in the North, where access to health services is precarious. The findings emphasize the need for territorially integrated strategies that combine climate adaptation, poverty reduction, and investments in resilient public health infrastructure.