Dennis, A.M., Murillo, W., de Maria Hernandez, F., et al. Journal of Acquired Immune Deficiency Syndromes (May 2013), Vol. 63 No. 1, pp. 135-141.
Through cross-sectional analysis, the authors compared social recruitment chains and HIV phylogenetic clusters-individuals who share HIV strains-among men who have sex with men (MSM) and female sex workers (FSWs) to understand contributing factors of HIV transmission in three cities in El Salvador. Individuals were recruited through respondent-driven sampling (RDS). Many HIV-positive individuals were identified through RDS, and by subsequently applying phylogenetic analysis. The results showed that 14 percent of MSM recruited were HIV-positive and many were recently infected. Of nearly 700 MSM and 760 FSWs who consented to HIV testing, 141 were diagnosed HIV-positive, with 84 percent (n=119) providing a specimen for genotypic sequencing. The majority (67 percent) who tested positive were MSM, and tended to be younger and recently infected, compared to FSWs. Both groups had some prevalence of antiviral drug resistance. Among MSM, 43 percent were members of phylogenetic clusters, demonstrating that RDS successfully identified transmission networks. However, few HIV transmissions linked directly to social recruitment. The results emphasize the need to diagnose and link HIV-positive individuals to care earlier, especially young MSM. The authors concluded that utilizing a combination of social and molecular biomedical data could benefit HIV prevention by reaching high-risk groups early.