We explored potential HIV transmission typologies that involve transgender women to obtain insights on sexual and needle-sharing networks as sources of HIV infection.
San Francisco residents diagnosed with HIV in care at public facilities who had available viral pol sequences from June 2001 through January 2016 were included in the analysis.
Viral sequence data were matched to the San Francisco HIV/AIDS Case Registry to obtain demographic and risk classification information. Transmission clusters with ≥2 cases were identified by bootstrap values ≥90% and mean pairwise genetic distances ≤0.025 substitutions per site.
Transgender women represented 275 of 5,200 patients; 86 were present in 70 clusters. Four typologies were hypothesized: 1) transgender women in clusters with men who have sex with men (MSM), 2) transgender women who inject drugs in clusters with cisgender women and men who inject drugs, 3) multiple transgender women in clusters with one man, and 4) multiple transgender women who do not inject drugs in clusters with men and cisgender women who inject drugs.
Transmission patterns of transgender women may stand apart from MSM epidemics. Transgender women clustered with people who inject drugs, and with men who have sex with transgender women and cisgender women. Aggregation of transgender women into the category of MSM may obscure understanding of how they acquire HIV and to whom they may transmit infection. Phylogenetic insights strengthen the case that HIV prevention programs for MSM may not be applicable to transgender women or their partners.
aDepartment of Medicine, University of California, San Francisco
bSan Francisco Department of Public Health.
Correspondence to Dr. Hong-Ha M. Truong, 550 16th Street, 3rd Floor, San Francisco, CA 94158; e-mail: Hong-Ha.Truong@ucsf.edu
Received 18 December, 2018
Revised 19 April, 2019
Accepted 17 June, 2019