Intersecting Epidemics: A Multilevel Syndemic Analysis of a Chikungunya Virus Epidemic in Colombia Through Clinical, Biological, and Socioeconomic Factors.

This study applied a syndemic framework to chikungunya virus (CHIKV) infection during the 2014-2015 Colombian epidemic, integrating biological and social determinants. A community-based cohort of 279 serologically confirmed adults from six cities was analyzed. Clinical, sociodemographic, and cytokine data were evaluated using multilevel and multivariate statistical approaches. Among 279 patients, 141 (50.5%) met World Health Organization (WHO) criteria for acute CHIKV infection. The cohort was predominantly female and of lower socioeconomic status (SES). The most frequent manifestations were arthralgia (91%), fatigue (58%), fever (50.5%), myalgia (45.9%), and rash (45.2%). Multivariate models identified IL-15, IL-17A, IL-12p40, MCP-1, and MIP-1α as significant correlates of fever, rash, and myalgia. Socioeconomic and ethnic factors influenced cytokine expression; Caucasian patients showed higher proinflammatory cytokine levels than Afro-American patients. Lower SES was associated with greater symptom burden. Network analyses revealed distinct immune signatures linking biological responses with clinical and demographic variables. Immune responses, clinical manifestations, and social disadvantages interact significantly in CHIKV infection. These findings support a syndemic model in which socioeconomic vulnerability amplifies disease impact, highlighting the need for integrated biosociological public health strategies, particularly targeting populations with low socioeconomic status.