Fiocruz presents in a webinar more optimistic forecasts for the 2026 dengue season
Researchers and public health managers took part on Friday (31/10/25) in the webinar Preparing for the 2026 dengue season: insights from predictive models, organised by the Scientific Computing Programme of Fiocruz (PROCC), linked to the Vice-Presidency of Education, Information and Communication, in partnership with The Global Health Network Latin America and the Caribbean (TGHN LAC).
The event had more than one thousand participants from around 50 countries, reflecting the growing international interest in Brazilian initiatives on predictive modelling applied to arbovirus surveillance.
The session was moderated by Fiocruz researcher Claudia Codeço and featured presentations by Codeço herself, Oswaldo G. Cruz (Fiocruz), Flávio Coelho (FGV), and Lívia Carla Vinhal Frutuoso, General Coordinator of Arbovirus Surveillance at the Brazilian Ministry of Health (MoH).
International challenge brought together 52 researchers
During the event, Codeço presented the InfoDengue project, while Flávio Coelho shared the results of the international challenge “InfoDengue–Mosqlimate Challenge 2025”, aimed at forecasting the 2026 dengue season. The initiative engaged 52 researchers from 15 teams worldwide to develop predictive models capable of estimating dengue incidence in Brazil and supporting strategic decision-making in public health.
72% reduction compared to 2024
Among the main findings, a combined ensemble model integrated the estimates of all participating algorithms. The projection indicates around 1.8 million probable cases in Brazil between October 2025 and October 2026, with 65% to 70% concentrated in the Southeast region. The forecast suggests a dengue season similar to 2023 or 2025, with no evidence of a scenario like 2024, when the country recorded 6.5 million probable cases, according to MoH data.
According to Lívia, this number of cases is still considered high, and effective management will require the engagement of society and local authorities in implementing prevention measures. Claudia highlighted that prevention actions carried out in November and December could significantly contribute to reducing cases during the season.
Ensemble model increases forecast accuracy
Flávio noted that the projection’s accuracy improved precisely because of the combination of models. “No single model was the most accurate across all states, which is why integrating them is so important. They bring together different perspectives on dengue dynamics and provide a more robust outlook for 2026. Our forecasts are optimistic for the coming year,” emphasised Coelho.
Oswaldo G. Cruz stressed the complexity of addressing diseases transmitted by vectors such as the Aedes aegypti mosquito, as they require considering multiple factors such as climate, human mobility, and acquired immunity. “Arboviruses are not a simple matter,” said Cruz.
MoH incorporates models into surveillance
In her presentation, Lívia Carla Vinhal Frutuoso explained how the Ministry of Health has been incorporating predictive modelling into the routine of epidemiological surveillance as part of a continuous process of preparation and decision-making. “Models are used to support surveillance, but they are not the only strategies adopted by the Ministry to prepare for future scenarios and define response strategies,” said Frutuoso.
The detailed technical report of the challenge is publicly available on the Mosqlimate platform, and the full webinar recording can be watched on the VideoSaúde/Fiocruz YouTube channel.
Written by Luisa Picanço (TGHN LAC/Fiocruz)