HIV-1-Syphilis Co-infection Associated with High Viral Load in Female Sex Workers in the Democratic Republic of the Congo

Abstract

Background: Sexually transmitted infections (STI) and HIV co-infection are common in countries where resources are limited constituting a leading public health issue. The negative impact of HIV transmission and acquisition are known. The aim of this study was to determine whether HIV-1-syphilis co-infection is associated with high HIV-1 viral load (VL) in female sex workers (FSWs) in the Democratic Republic of the Congo (DRC). Methods: Sera from 411 FSWs tested HIV+ in a national DRC HIV/STI Integrated Biological and Behavioral Surveillance Survey (IBBS) conducted between December 2012 and January 2013. HIV and syphilis testing were performed according to validated DRC national testing algorithms used by the National AIDS Control Program (PNLS). VL was measured according to Abbot m2000sp and m2000rt protocols. HIV-1-syphilis co-infection proportion was determined and multivariate analyses were used to identify factors associated with higher VL in HIV-1-syphilis co-infected FSWs. Results: Of 411 HIV-infected FSWs, 19.2% (95% CI: 15.4 – 23.0) were co-infected with syphilis. The mean HIV-1 VL in HIV-1-positive FSWs co-infected with syphilis [2.9 log10 HIV RNA/mL (95% CI: 2.49 – 3.29)] was higher compared with those not co-infected with syphilis [2.2 log10 HIV RNA/mL (95% CI: 1.97 – 2.46)]. Multivariate analysis showed that syphilis co-infection was associated with high HIV-1 VL (aOR [95% CI] = 1.90 [1.03, 3.52]) but HIV-1VL was not influenced by age, education level, duration in sex profession, abnormal fluid, and genital sore. Conclusion and Implications for Translation: HIV-1 Syphilis co-infection was associated with higher HIV-1 VL. Preventing FSWs from getting STIs and screening HIV-infected individuals for STIs and providing them with appropriate treatment could impact the transmission of HIV from FSWs to their clients.