Secondary Logo

Journal Logo

Institutional members access full text with Ovid®

How are transgender women acquiring HIV? Insights from phylogenetic transmission clusters in San Francisco

Truong, Hong-Ha M.a; O’Keefe, Kara J.b; Pipkin, Sharonb; Liegler, Teria; Scheer, Susanb; Wilson, Erinb; McFarland, Willib

doi: 10.1097/QAD.0000000000002318

Objective: We explored potential HIV transmission typologies that involve transgender women to obtain insights on sexual and needle-sharing networks as sources of HIV infection.

Design: San Francisco residents diagnosed with HIV in care at public facilities who had available viral pol sequences from June 2001 to January 2016 were included in the analysis.

Methods: Viral sequence data were matched to the San Francisco HIV/AIDS Case Registry to obtain demographic and risk classification information. Transmission clusters with at least two cases were identified by bootstrap values at least 90% and mean pairwise genetic distances 0.025 or less substitutions per site.

Results: Transgender women represented 275 of 5200 patients; 86 were present in 70 clusters. Four typologies were hypothesized: first, transgender women in clusters with MSM; second, transgender women who inject drugs in clusters with cisgender women and men who inject drugs; third, multiple transgender women in clusters with one man; and fourth, multiple transgender women who do not inject drugs in clusters with men and cisgender women who inject drugs.

Conclusion: 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, San Francisco, California, USA.

Correspondence to Dr Hong-Ha M. Truong, PhD, MS, MPH, Department of Medicine, University of California, San Francisco, 550 16th Street, 3rd Floor, San Francisco, CA 94158, USA. E-mail:

Received 18 December, 2018

Revised 19 April, 2019

Accepted 17 June, 2019

Copyright © 2019 Wolters Kluwer Health, Inc.