Acute respiratory viral diseases in Amazonas, Brazil: epidemiological patterns and implications for health surveillance

BACKGROUND: Acute respiratory viral diseases are a major public health challenge in the Brazilian Amazon, where ecological, logistical, and social factors shape patterns of transmission and response. METHODS: This study aimed to analyze the epidemiological patterns and temporal-spatial distribution of Influenza-like illness (ILI) and severe acute respiratory syndrome (SARS) in the state of Amazonas, Brazil, between 2015 and 2025, distinguishing SARS-CoV-2 and non-SARS-CoV-2 etiologies using data from OpenDataSUS. RESULTS: Incidence peaks occurred in early 2021 and 2022, with pronounced regional disparities. The highest burdens were concentrated in specific municipalities, with Manaus exhibiting an intermediate incidence and playing a central role in case notifications and healthcare provision. DISCUSSION: We describe the integration of surveillance systems, laboratory networks, and healthcare infrastructure, which enabled improvements in diagnosis, monitoring, and care. The region's response model, centered in Manaus, includes primary-to-tertiary care coordination, molecular diagnostics, telemedicine, and mobile health units for Indigenous and remote areas. Research efforts during the COVID-19 pandemic provided critical insights into therapeutic strategies, immunopathology, and long-term sequelae, while also highlighting persistent inequities and diagnostic gaps. Our findings underscore the co-circulation of multiple respiratory pathogens and the need for continued genomic and syndromic surveillance. Future strategies must address regional disparities, support decentralized diagnostics, and expand clinical research. Strengthening integrated health systems in the Brazilian Amazon is essential for timely, equitable responses to emerging respiratory threats.