Seasonality in Dengue Incidence in Brazil Over the Last 10 Years: An Epidemiological Analysis

Abstract

Dengue is one of the most prevalent arboviruses in Brazil, characterized by a seasonal incidence pattern. This study aims to analyze the seasonality of dengue in Brazil from 2015 to 2024, assessing the temporal distribution of cases and their possible relationships with climatic and epidemiological factors. This is a descriptive-analytical epidemiological study based on secondary data from the Notifiable Diseases Information System (SINAN), extracted from DATASUS. Dengue notifications in Brazil from 2015 to 2024 were analyzed, considering the monthly distribution of cases. The data showed a seasonal pattern, with higher incidence between January and May, accounting for over 70% of annual cases. In 2024, the first three months of the year concentrated 45% of the notifications. The year-over-year analysis revealed epidemic cycles, with high-transmission periods followed by years of lower incidence. The year 2024 recorded an alarming increase of 326.6% compared to 2023. The observed seasonality is associated with climatic factors, such as temperature and rainfall, which influence vector proliferation. Additionally, the circulation of different serotypes contributes to epidemic cycles. The significant increase in cases in 2024 suggests the need to strengthen control and prevention measures, including vaccination and intensified actions during critical months. Dengue seasonality in Brazil should be considered in public policy planning. Preventive strategies based on the disease’s temporal dynamics can optimize resources and reduce the burden of dengue in the country.