Analysis of spatial and demographic factors associated with chikungunya in Espírito Santo state, Brazil.

BACKGROUND Chikungunya (CHIK) emerged in Brazil in 2014 and since then several epidemics have been observed. This study aims to describe the spatial, social and demographic characteristics of individuals affected by CHIK in Espírito Santo state. METHODS A cross-sectional study was performed using data from individuals with a confirmed diagnosis of CHIK in Espírito Santo state, Brazil, from 2018 to 2020. Monthly incidence was calculated and annual spatial distribution maps were constructed. Statistical analysis using the χ2 test identified associations between disease occurrence and sociodemographic variables. RESULTS In the period and area analysed, a CHIK epidemic occurred in 2020, with an incidence of 219.8 cases per 100 000 inhabitants. The southern and central regions of Espirito Santo state harboured a risk five times greater than the others in the epidemic region. Females (odds ratio [OR] 1.65 [95% confidence interval {CI} 1.58 to 1.72]), black people (OR 1.22 [95% CI 1.13 to 1.33]), individuals with ≤11 y of education (OR 1.48 [95% CI 1.37 to 1.61]) and the elderly (OR 7.49 [95% CI 6.53 to 8.59]) had a greater risk for the disease. CONCLUSIONS CHIK stands as an emerging public health problem in Brazil since its introduction in 2014. Espírito Santo suffered a substantial epidemic in 2020, possibly due to outbreaks in neighbouring states. The population at risk should be prioritized in healthcare, considering the morbidity potential of the disease.