Epidemiology of HIV and Syphilis in a Sub-Saharan African Military Population

Background: Risk behaviors associated with HIV are thought to be similar to those associated with syphilis. Determining risk behaviors associated with active syphilis infection may provide information useful to HIV prevention programs.

Methods: A cross-sectional study designed to estimate HIV and syphilis prevalence and associated demographic and risk behaviors was conducted from September to December 2014 in a sub-Saharan African military population. Questionnaires were completed via computer-assisted personal interviews with trained study personnel guiding the participants through the survey. Confidential HIV and syphilis rapid tests were performed, and results were linked to anonymous survey data. The sample included 2100 male and female military personnel aged 18 years and older from military units in each of the military zones. A stratified proportional sampling scheme was used to randomly select participants within each military unit.

Results: The prevalence of HIV and syphilis was 3.3% and 6%, respectively, in this population. Gender varied significantly by HIV status, with men less likely to be HIV positive (80%) than HIV negative (93%); however, women were more likely to be HIV positive (20%) than HIV negative (7%) (P<.001). HIV-positive participants had a mean age of 35 years. Current marital status also varied significantly by HIV status; HIV-positive participants were less likely to be married than HIV-negative participants (77% vs. 82%) (P<.001). In contrast to HIV, syphilis-positive participants were almost exclusively male (95%), younger, less educated, and Muslim.  There were no differences in key risk factors such as number of casual sexual partners, alcohol misuse, drug use, or mental health conditions.

Conclusions: The predominantly male focus of syphilis implies a different epidemiology than HIV. Syphilis screening in this military population may represent a safe and effective means of identifying a subset of individuals at high risk for HIV for targeted public health programming.