By Ayden Scheim

In response to mounting evidence of the prevention benefits of pre-exposure prophylaxis (PrEP) use by HIV-negative gay and bisexual men, a discussion recently emerged on social media about the perceived exclusion of trans men1 who have sex with men from PrEP research studies.

In fact, trans men participate in many HIV prevention research studies, whether or not they are identified as trans when results are reported. Some do not identify as trans, but rather as men of trans experience or transitioned men, and are happy to check the “male” box without qualification. Other studies have explicitly included trans men and allowed them to self-identify. Regardless, some were upset that when results were reported, PrEP effectiveness among trans men was not addressed. In response, a number of well-intentioned non-trans men voiced their support for greater inclusion of trans men in biomedical and other HIV prevention research. While these statements are a testament to the progress gay and bisexual men’s communities are making in embracing men of trans experience, I feel compelled to offer a reality check about the inclusion of trans men in HIV prevention research.

According to a recent estimate,2 about one in 200 people are trans. Therefore, unless greatly oversampled, trans men will never represent a large enough subgroup of a study to allow for well-powered comparisons of efficacy or effectiveness between trans and non-trans men. Further complicating matters is that we would likely see lower incidence rates among trans men overall, requiring even larger numbers to detect an effect. Trans people are not unicorns! We can cautiously infer from research on non-trans people. For instance, we can look to basic science research showing lower concentrations of tenofovir (one of the two drugs in Truvada) in vaginal and cervical versus rectal tissues to learn about how PrEP may work differently for trans men who have vaginal intercourse (e.g. requiring more frequent dosing, or a longer period to become efficacious at the beginning of use). Where we do need to find out more about prevention issues specific to trans people, studies that are trans-specific provide better opportunities to ask targeted questions, and to explore heterogeneity within trans communities. Inclusion of trans people in broader studies is important for identifying disparities, but is often less useful for identifying potential remedies for such disparities. While some gay, bi, and queer trans men are at risk for, or living with HIV, the impact of HIV in trans communities is largely experienced by trans women, who are at incredibly high risk of infection in many regions.3 At the moment, we don’t have evidence to suggest a similar HIV epidemic among trans men, in any setting. While we need more, and better-quality, data on HIV prevalence and incidence in trans populations,4 we can safely conclude that trans women should be prioritized in prevention research. Yet, trans women represented a pitiful 0.2 per cent of participants in PrEP trials that had reported results as of 2013.5

Moving forward, prevention research and interventions (e.g., PrEP demonstration projects) that focus on trans women are needed, rather than problematically lumping them in with men who have sex with men. While prevention, treatment, and care efforts for gay and bisexual men must accommodate the experiences and needs of trans men affected by HIV, gay and bisexual men (trans and non-trans) should be raising our voices to ensure that increased resources are dedicated to HIV prevention for trans women.

Ayden Scheim is a PhD Candidate, Trudeau Foundation Scholar, and Vanier Scholar in epidemiology and biostatistics at Western University in London, Ontario. Over the past decade, he has been involved in a number of community-based trans health research, promotion and education initiatives, including work with the Trans Men’s Working Group of the Ontario Gay Men’s Sexual Health Alliance.

1 I use trans men here to refer to those who are assigned a female sex at birth, but identify as male or masculine. Similarly, I use trans women as shorthand to refer to those who were assigned male at birth, but identify as female or feminine. These are imperfect terms, as many trans people do not necessarily identify as “men” or “women.”

2 Conron KJ, Scott G, Stowell GS, Landers SJ. Transgender health in Massachusetts: results from a household probability sample of adults. American Journal of Public Health. 2012;102(1):118–22.

3 Baral SD, Poteat T, Strömdahl S, Wirtz AL, Guadamuz TT, Beyrer C. Worldwide burden of HIV in transgender women: a systematic review and meta-analysis. Lancet Infectious Diseases. 2013;13(3):214–22.

4 As trans status is not captured in HIV testing data and other surveillance data sources, seroprevalence estimates for trans women rely almost exclusively on convenience sampling, often from venues where we would expect higher prevalence (e.g. sexual health clinics and HIV prevention programs). In addition, we are not able to estimate HIV prevalence for trans people in Canada.

5 Escudero DJ, Kerr T, Operario D, Socías ME, Sued O, Marshall BDL. Inclusion of trans women in pre-exposure prophylaxis trials: a review. AIDS care. 2015;27(5):637–41.