Identification of risk areas and factors associated with the 2019 measles epidemic in the State of São Paulo, Brazil

Abstract

This study aimed to analyze the occurrence of clusters and factors associated with the resurgence of measles cases from the largest epidemic of the post-elimination period in the State of São Paulo, Brazil, in 2019. Sociosanitary and care factors were analyzed by zero-inflated Poisson (ZIP) and ZIP models with structured and unstructured spatial effect. The SCAN statistic was used to analyze the occurrence of case clusters. Clusters of high-risk cases were identified in municipalities that make up the intermediate region of São Paulo. In the ZIP model, the following variables were observed as risk factors at the municipal level: household heads under 18 years old (adjusted RR =0 1.39; 95%CrI: 1.27-1.53), inequality in income distribution (adjusted RR = 36.67; 95%CrI: 26.36-51.15), unemployment in people over 18 years old (adjusted RR = 1.10; 95%CrI: 1.08-1.12), and non-existent street lighting (adjusted RR = 1.05; 95%CrI: 1.04-1.05). In the ZIP models with structured and unstructured spatial effect, the following variables were observed as risk factors: household heads under 18 years old (adjusted RR = 1.36; 95%CrI: 1.04-1.90) and inequality in income distribution (adjusted RR = 3.12; 95%CrI: 1.02-9.48). In both models, the coverage of health agents was presented as a protective factor. The findings reinforce the importance of intensifying measles surveillance actions articulated to the Family Health Strategy, especially in areas with greater social vulnerability, to ensure equitable and satisfactory vaccination coverage and reduce the risk of reemergence of the disease.