Climate change and Plasmodium vivax Malaria Risk in Brazil: Developing adaptive tool for Brazilian Municipalities

Climate change impacts ecosystems and health sectors, increasing the incidence of climate-sensitive diseases like malaria, mainly in tropical countries. This study assesses malaria risk, particularly related to Plasmodium vivax, under climate change scenarios for 2030 and 2050 for two greenhouse gas emission scenarios (RCP 4.5 and RCP 8.5), using the AdaptaBrasil MCTI approach, which supports decision-makers in enhancing climate adaptation strategies. A multilevel analysis was employed to identify key climate variables influencing malaria incidence (temperature, relative humidity, and the Simple Daily Intensity Index (SDII)). A logistic Binary Model was applied to estimate the climate threat associated with malaria incidence in all Brazilian municipalities for baseline and future scenarios. The Vulnerability Index, comprising Sensitivity and Adaptive Capacity dimensions, highlighted social susceptibility and healthcare access as crucial factors driving higher vulnerability. Road networks and land use factors shaped the Exposure Index, and the Climate Threat Index was based on maximum temperature, SDII, and relative humidity. Under both scenarios, the findings show a growing malaria risk across Brazil, with the most significant impact in the Amazon, expanding to the other regions, mainly the Southeast and Northeast, by 2050. Maximum temperature increases (β = 0.35) emerged as the most influential factor, followed by SDII (β = 0.19) and relative humidity (β = 0.12). These results emphasize the need for targeted public health and environmental interventions to address rising malaria risks, particularly in the Amazon. This study offers critical insights into the relationship between climate change and malaria, informing future policies for climate adaptation and public health preparedness in Brazil.