Syphilis and HIV Co-infection in Mississippi: Implications for Control and Prevention.

Syphilis and HIV are important public health issues in the United States, especially in the southeastern region. This study aimed to determine and describe the co-infection pattern in Mississippi by using a case-controlled design to analyze cases diagnosed with syphilis or HIV from 2007 to 2016. Direct matching was employed to identify cases that were co-infected during the same calendar year, and binary logistic regression analysis was used to determine predictors of co-infection. Results showed that 1736 (34.0%) of syphilis and HIV cases were co-infected during the same calendar year. Binary logistic regression results demonstrated that race, gender, age group, and exposure category were independently associated with co-infection status. These analyses highlighted the progressive increase of co-infection rates in Mississippi. Collaboration between STI/HIV surveillance teams may identify high-risk individuals and reduce transmission of both diseases.