33rd International Dynamics & Evolution of Human Viruses

Phylogenetic clustering analysis shows diverse transmission contexts for transgender people living with HIV in British Columbia, Canada

May 21, 2026, 11:30 AM

20m

Poster Transmission dynamics & clusters Transmission Dynamics & Clusters

Speaker

Mx Giuli Sucar (Joy Lab, BC-CfE, University of British Columbia)

Description

BACKGROUND:
Transgender (trans) people are frequently marginalized in HIV surveillance. Trans women are often grouped with gay and bisexual men (GBM), while trans men and non-binary people are commonly excluded. This can perpetuate inequity in prevention and care.

METHODS:
We analyzed clinical data from 15,299 individuals living with HIV in British Columbia (BC) Canada (1999-2022). Gender was available for 15,122 individuals (including 91 trans women, 13 trans men, non-binary not collected). HIV pol sequences available for 10,724 individuals (not available for ART experienced clients) were utilized to infer phylogenetic trees under a maximum likelihood model framework using IQ-TREE. Transmission clusters were defined for >5 individuals with a pairwise patristic distance <0.02 substitutions per site and >90% bootstrap support. Using Mann-Whitney tests, 1000 permutations and Benjamini-Hochberg correction, clusters were compared between trans-inclusive and not, regarding their size and rates of reported transmission risk (mainly GBM, heterosexual (HET) or people who inject drugs (PWID)). Trans people’s sexual exposures with men were reported as GBM or HET, suggesting semantic ambiguity and misgendering.

RESULTS:
Clustered cases include 4,053 cisgender, 28 transgender, and 53 people of unknown gender. Among 209 clusters, 23 were trans-inclusive. Trans people were distributed across clusters dominated by different risk exposure categories. After accounting for size distortions through permutations, trans-inclusive clusters showed no statistically significant differences in size or composition, except for a modest enrichment for GBM members.

CONCLUSIONS:
The small number of HIV+ trans people in BC are embedded in diverse transmission networks, highlighting limitations of collapsing trans women into GBM and the near invisibility of trans men and non-binary individuals in surveillance systems. Our findings support the need for trans-inclusivity in existing harm reduction services, trans-specific HIV prevention and care strategies (such as gender affirming PrEP systems), and surveillance practices accurately reflecting diverse gender identities and risk contexts.