A Global Scoping Review of the Factors Associated with HIV and Syphilis Co-Infection: Findings from 40 Countries

Human immunodeficiency virus (HIV)–syphilis co-infection poses a threat to certain populations, and patients may have considerably poorer health outcomes due to these infections. Our objective was therefore to provide a scoping review of the literature regarding the factors associated with HIV–syphilis coinfection. We searched PubMed, Scopus, and Web of Science, and produced a total of 1412 articles. After completing the screening process as per the Preferred Items for Systematic Review and Meta-Analysis extension for Scoping Review (PRISMA-ScR) guidelines, a total of 109 articles were eligible for inclusion. A total of 68,634 co-infected patients were included in our review. Findings from studies across 40 countries demonstrated that males—particularly men who have sex with men—compose the overwhelming majority of co-infected cases. Additional risk factors include a low CD4 cell count, current or past sexually transmitted infections, and a high number of sexual partners. Our findings have important implications in guiding public health programs across the globe that aim to lower the rates of HIV–syphilis co-infection. More research is also needed on the role of educational attainment, comorbidities, and consistent condom usage regarding the risk for co-infection.