Transgender women are one of the fastest growing population of HIV-positive people in the U.S.: According to a 2009 NIH study, one third of trans women are HIV-positive–that number leaps to 56% for trans women of color.

This summer at the International AIDS Society Conference in Paris, researchers reported that concerns about taking antiretroviral medication while on hormone therapy have caused many trans women to stop their HIV treatment.

"Despite all indications that transgender women are a critical population in HIV care, very little is known about how to optimize co-administration of ART [antiretroviral therapy] and hormonal therapies in this population," said Dr. Jordan Lake of UCLA's David Geffen School of Medicine. "This void of information may mean some transgender women forgo life-sustaining HIV medications, identity-affirming hormone therapy, or some combination of the two."

Both hormone therapy and ART have potential side effects—substantial ones—but little is known about their safety and effectiveness when combined. What few studies have been commissioned have been on post-menopausal cisgender women using HRT: According to a report by to Callen-Lorde Community Health Center's Asa Radix, no published studies have examined interactions between ART and the types and doses of estrogen found in feminizing regimens. (Findings are also incomplete on the efficacy of PrEP on trans women taking hormones.)

"Making sure we are meeting the needs of transgender women living with HIV is key to addressing this pandemic," adds Dr. Judith Currier, vice-chair of the AIDS Clinical Trials Network. "We need to provide an evidence-based response to these understandable concerns so that this key population and their sexual partners may reap the full benefits of effective HIV care."

Lake's team surveyed 87 transgender women at an AIDS clinic in Los Angeles, where more than half were HIV positive and 69% were taking hormone therapy.

Many prioritized hormones over anti-retrovirals: “They feel that the HIV meds would mess with the hormones," said one interviewee. "[And] they want the hormones to work okay.”

Of those in the NIH survey, 40% stopped taking HIV medications altogether and 49% discussed their fear of side effects with their doctor. (The remainder "navigated the problem outside the health care system.")

The study also found that a quarter of trans women taking hormones were doing so without a doctor's supervision. For HIV-positive patients, that number shot up to 34%.

“Not much HIV-prevention messaging is aimed toward or accessible to trans people,” Cyd Nova, harm-reduction coordinator at San Francisco’s St. James Infirmary, told HIV Plus. Nova added that most HIV-prevention programs are geared toward gay men.

With a White House only too eager to roll back LGBT advances and eliminate health-care relief, the problem isn't going away any time soon.