Brazil could reach 1.8 million probable cases of dengue in 2026, with 54% expected in the state of São Paulo. Next year is projected to be the second highest in number of infections since 2010.
This estimate, covering the 12-month period starting in October 2025, is the result of the InfoDengue-Mosqlimate Dengue Challenge, an international collaboration between InfoDengue, Mosqlimate, Fiocruz (Fundação Oswaldo Cruz), and FGV (Fundação Getulio Vargas).
Analysis suggests a year with epidemic characteristics, though not reaching the extremes of 2024.
The study involved 52 researchers from South Africa, Germany, Saudi Arabia, brazil, Spain, the United States, Italy, and the United Kingdom, aiming to develop and train predictive dengue models in Brazil and improve outbreak predictions using climatic and epidemiological data.
A total of 15 research teams participated, submitting 19 different models predicting dengue cases. These predictions were then unified.
Projections indicate levels lower than those observed in 2024-which saw over 6.5 million probable cases and 6.3 thousand deaths-and similar to 2025, which totaled 1.6 million infections and 1,761 deaths by December 6.
Acre and Tocantins (North), Rio Grande do Norte (Northeast), São Paulo, minas Gerais and Espírito Santo (Southeast), and all federative units in the South and Central-West are expected to exceed an incidence rate of 300 cases per 100,000 inhabitants, considered an epidemic by the WHO (World Health Organization).
However, in 2026, Paraná, Rio Grande do Sul, São Paulo, Acre, and Amapá are projected to have lower incidence rates than this year. Higher rates are expected in Santa Catarina, Minas Gerais, Distrito Federal, Mato Grosso do Sul, and Tocantins, while the remaining areas should see rates similar to the current levels.
Researchers are especially concerned about Minas Gerais, due to its consistently high dengue numbers in recent years and current growth projections.
“There was practically no dengue in the South, and for a few years now the region has consistently been the runner-up for cases. The leaders were the Southeast, Central-West, and Northeast. The Northeast, in recent years, has registered few cases compared to the Southeast. And the South has a large virgin population, which has never had dengue,” explains Kleber Luz, coordinator of the Arboviruses Committee at SBI (Brazilian Society of Infectious Diseases) and consultant for arboviruses at PAHO (Pan American Health Organization), arm of the WHO in the Americas and professor at the Federal University of Rio Grande do Norte. The specialist did not participate in the study.
according to Flávio Codeço Coelho, study coordinator and professor at EMAp/FGV (Fundação Getulio Vargas School of Applied Mathematics), investments in prevention…
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