Effectiveness, safety, and implementation outcomes of a decentralization program to deliver antivenoms in the Western Brazilian Amazonia: The SAVING program

BACKGROUND: Snakebite envenoming (SBE) is a major cause of morbidity in mortality in low-income and middle-income countries. In Brazil, SBE disproportionately affects Indigenous populations. Limited access to antivenom treatment is a key determinant of poor outcomes in these populations. We evaluated the effectiveness and feasibility of a decentralized model of antivenom delivery in Indigenous primary health settings in the Brazilian Amazon. METHODS: An implementation study was carried out in four Indigenous Health Poles across Amazonas state, Brazil. Effectiveness was assessed using a pre-post design based on national surveillance data, comparing time to antivenom administration, clinical severity, specific clinical manifestations, and case-fatality before and after implementation. Occurrence of early adverse reactions from antivenom treatment was assessed. Qualitative data were collected through semi-structured interviews with Indigenous patients, health-care providers, and health-system managers to assess acceptability, adoption, feasibility, fidelity, and sustainability of the intervention. PRINCIPAL FINDINGS: Among 125 patients treated after decentralization, the proportion receiving antivenom within 6 hours after bite was significantly higher than under usual care (75.8% vs 40.8%; OR 4·5, 95% CI 2·6-7·9). Proportion of mild envenomations were more frequent after decentralization (50.4% vs 32.7%; OR 2·1, 95% CI 1·2-3·6). Five deaths (4%) were reported in the usual care group and one death (0.8%) was reported in the intervention group (5.3, 95% CI 0.6-45.9). Three (2.4%) patients had mild skin adverse reactions, which were properly managed without need for hospital transfer. A high acceptability was observed among Indigenous users and health providers, combined with good compliance by the providers with the clinical protocol and improved trust in local health services. Health providers and managers at all levels expressed willingness to support sustained antivenom delivery in the study settings and scale up to other Indigenous areas. CONCLUSION: Decentralization improved access to antivenom treatment and reduced poor clinical outcomes. Culturally adapted, decentralized care can be safely implemented in remote settings, with important implications for equitable health system strengthening.