Spatial distribution of the relative risk of Zika virus disease in Colombia during the 2015–2016 epidemic from a Bayesian approach

Objective: To determine the spatial distribution of the risk of Zika virus disease in each region of Colombia during the 2015–2016 epidemic. Methods: An ecological study was designed to estimate the risks for each Colombian region using first-order neighbors, covariate effects, and three adjacent periods of time (beginning, development, and end of the epidemic) to analyze the spatial distribution of the disease based on a Bayesian hierarchical model. Results: Spatial distribution of the estimated risks of Zika virus disease showed that it increased in a strip that crosses the central area of the country from west to east. Analysis of the three time periods showed greater risk of the disease in the central and southern zones—Arauca and Santander—where the increase in risk was four times higher during the peak phase compared with the initial phase of the outbreak. Conclusion: In the identified high-risk areas, integrated surveillance systems for Zika virus disease and its complications must be strengthened to provide up-to-date and accurate epidemiological information. This information would allow those involved in policy and decision making to identify new outbreaks and risk clusters, enabling more focused and accurate measures to target at-risk populations.