<p><strong>PURPOSE: </strong>The aim of the study was to characterize perceived social support for young men and transgender women who have sex with men (YM/TWSM) taking HIV pre-exposure prophylaxis (PrEP).</p>

<p><strong>METHODS: </strong>Mixed-methods study of HIV-negative YM/TWSM of color prescribed oral PrEP. Participants completed egocentric network inventories characterizing their social support networks and identifying PrEP adherence support figures. A subset (n&nbsp;= 31) completed semistructured interviews exploring adherence support and qualities of PrEP support figures. We calculated proportions of role types (e.g., family), individuals disclosed to regarding PrEP use, and PrEP-supportive individuals within each participant network. Interviews were analyzed using an inductive approach.</p>

<p><strong>RESULTS: </strong>Participants (n&nbsp;= 50) were predominately African American men who have sex with men. Median age was 22&nbsp;years (interquartile range: 20-23). Biologic family were the most common support figures, reported by 75% of participants (mean family proportion .37 [standard deviation (SD): .31]), followed by 67% reporting friends (mean friend proportion .38 [SD: .36]). Most network members were aware (mean disclosed proportion .74 [SD: .31]) and supportive (mean supportive proportion .87 [SD: .28]) of the participants' PrEP use. Nearly all (98%) participants identified ≥1 figure who provided adherence support; more often friends (48%) than family (36%). Participants characterized support as instrumental (e.g., transportation); emotional (e.g., affection); and social interaction (e.g., taking medication together). Key characteristics of PrEP support figures included closeness, dependability, and homophily (alikeness) with respect to sexual orientation.</p>

<p><strong>CONCLUSIONS: </strong>Although most YM/TWSM identified family in their support networks, friends were most often cited as PrEP adherence support figures. Interventions to increase PrEP adherence should consider integrated social network and family-based approaches.</p>

<p>We aimed to discover barriers and facilitators of HIV pre-exposure prophylaxis (PrEP) adherence in young men and transgender women of color who have sex with men (YMSM/TW). Short-term and sustained adherence were measured by urine tenofovir concentration and pharmacy refills, respectively. Optimal adherence was defined as having both urine tenofovir concentration consistent with dose ingestion within 48&nbsp;h and pharmacy refills consistent with ≥ 4 doses per week use. Participants completed semi-structured interviews exploring adherence barriers and facilitators. Participants (n = 31) were primarily African-American (68%), mean age 22&nbsp;years (SD: 1.8), and 48% had optimal adherence. Adherence barriers included stigma, health systems inaccessibility, side effects, competing stressors, and low HIV risk perception. Facilitators included social support, health system accessibility,&nbsp;reminders/routines, high HIV risk perception, and personal agency. Our findings identify targets for intervention to improve PrEP adherence in these populations, including augmenting health activation and improving accuracy of HIV risk perception.</p>