HIV transmission networks among transgender women in Los Angeles County, CA, USA: a phylogenetic analysis of surveillance data

Abstract

SUMMARY Background Transgender women (TGW) are among the groups at highest risk for HIV infection, with a prevalence of 27.7% in the United States, but despite this high risk, TGW have documented high rates of undiagnosed HIV infection. We propose that this disparity can be addressed by characterizing TGW in a molecular transmission network to prioritize public health activities. Methods Since 2006, HIV pol sequences from drug resistance testing have been reported to Los Angeles County (LAC) Department of Public Health and linked to demographic data, gender, and HIV transmission risk factor data for each case in the enhanced HIV/AIDS Reporting System (eHARS). We reconstructed a molecular transmission network using HIV-TRACE (pairwise genetic distance threshold of 0.015 substitutions/site) from the earliest pol sequences from 22,398 unique individuals, including 412 (2%) self-identified TGW. We examined the possible predictors of clustering using multivariate logistic regression. We characterized the genetically-linked partners of TGW and calculated assortativity—the tendency for persons to link to other persons with the same attributes—for each transmission risk group. Findings We found that 36% of individuals (8,133/22,398) clustered in the network across 1,722 molecular transmission clusters. TGW who indicated a sexual risk factor clustered at the highest frequency in the network: 147/345 (42.6%) linked to at least one other person (p<0.001). TGW were assortative in the network (0.06; p<0.001), indicating that they tended to link to other TGW. TGW were more likely than expected to link to other TGW and cisgender men who did not identify as men who have sex with men (MSM). TGW were less likely than expected to link to MSM, despite the high prevalence of HIV among MSM. TGW were distributed across 126 clusters, and cis-individuals linked to one TGW were 9.2 times more likely to link to a second TGW than other individuals in the surveillance database. Reconstruction of the transmission network is limited by sample availability, but sequences were available for >40% of diagnoses. Interpretation TGW in LAC were more likely to cluster than any other risk group, suggesting high transmission rates—despite the small number of TGW in the network. TGW tended to cluster with other TGW, indicating shared risk activities (i.e., linked directly or through shared partners). This assortativity, and the observed tendency for linkage with cisgender men who did not identify as MSM, demonstrates the potential to use molecular epidemiology to both identify clusters likely to include undiagnosed HIV-infected TGW and improve the targeting of public health prevention and treatment services to TGW.

Contribution of transgender sex workers to the complexity of the HIV-1 epidemic in the metropolitan area of Milan

“…Estimates related to the main Italian metropolitan areas indicated the presence of a fluctuating but consistent population of about 3000 and 2000 TSWs in Rome and Milan, respectively (http://www.liberazionesperanza.it/wp-content/uploads/2018/05/2-MAPPATURA-NAZIONALE-DELLA-PROSTITUZIONE-DI-STRADA-27-ottobre.pdf). A recent study14 evaluated transmission networks in transgender woman; however, the major limitation of this work is that no data could infer about directionality of the transmission with the consequent impossibility to distinguish between transmitters and recipients. With the purpose to clarify this point, we adopted advanced phylogenetic methods that permit us to identify viral fluxes and the most probable country of HIV acquisition.…”

“…Despite recent data studied how transgender woman acquired HIV infection using phylogenetic approach to reconstruct transmission clusters,14 15 to date no study has been undertaken to establish whether South American TSWs have been infected in their country of origin or acquired HIV-1 infection where they practice commercial sex. In this context, molecular data may trace the country of infection and make inferences on the possible source of individual strains when epidemiological data are lacking or incomplete.…”

A View of Human Immunodeficiency Virus Infections in the North-West Region of Romania

“…Early presentation to the AIDS center could be the consequence of an increased level of information and awareness regarding HIV infection. More men were diagnosed at an early stage of infection and more women in the late stage of infection at the moment of diagnosis (Table 1), and the observed gender difference could be explained by the stigma associated with HIV infection, which carries a higher burden for women than men [24].…”

HIV Prevention Concepts—Counter Movements Challenging Societies

“…It should be noted that misclassifications may have occurred concerning "HIV-1 infections between men" [16] [17]. Furthermore, the impact of sexual networks between transgender women and cisgender men needs further studies [18].…”