Epidemiological Profile of Zika Virus Infection in Brazil Between 2015 and 2025: Analysis of Reported Cases and Mortality

Background/Objectives: Zika virus (ZIKV) infection remains an important public health concern due to its association with neurological complications and congenital malformations. This study aimed to analyze the epidemiological profile of reported ZIKV cases in Brazil between 2015 and 2025. Methods: This was a retrospective ecological time-series study using secondary data from the Notifiable Diseases Information System (SINAN/DATASUS). Temporal, spatial, and demographic distributions were analyzed, as well as cumulative incidence and case fatality according to age. Results: Between 2015 and 2025, 193,194 confirmed ZIKV cases were reported in Brazil. Significant annual variation was observed (χ2 = 920.675; df = 10; p < 0.0001), with a marked peak in 2016 (n = 138,025; 71.4%), followed by a substantial decline. The distribution across macro-regions was significantly heterogeneous (χ2 = 55.509; df = 4; p < 0.0001), with the Southeast (n = 84,107; 43.5%) and Northeast (n = 56,882; 29.4%) accounting for the highest absolute numbers of cases. Cases were predominant among females (n = 129,426; 67.0%; 95% CI: 66.78–67.20%; p < 0.0001) and adults aged 20–39 years (n = 81,661; 42.3%). The overall case fatality was 0.04%, with significant age-related (χ2 = 98.30; df = 4; p < 0.0001), the highest case fatality rates occurred among children younger than 1 year (0.35%) followed by individuals aged 1–19 years and those aged ≥60 years, both with a case fatality rate of 0.05%. Conclusions: ZIKV transmission in Brazil showed marked temporal, geographic, and demographic heterogeneity. Although cases declined after the 2016 epidemic peak, ZIKV remains an important public health concern, with persistent regional differences in disease burden.