Globally, transgender women (TW) experience a disproportionately high HIV burden. Pre-exposure prophylaxis (PrEP) offers an effective prevention tool, yet its widespread implementation among TW remains limited due to challenges in access, acceptability, and adherence. Studies indicate low PrEP acceptability among TW, often stemming from mistrust of medical establishments and prioritization of feminizing hormone therapy. These factors contribute to lower PrEP adherence, as evidenced by TW subgroups in the iPrEx trial. Peru lacks a public PrEP program; access is limited to demonstration projects and research studies, making it prohibitively expensive for many economically vulnerable TW. Social networks present a potential avenue for increasing PrEP awareness and acceptability within hard-to-reach populations. Research among men who have sex with men (MSM) in the US demonstrates the crucial role of social networks in disseminating PrEP information and providing support. However, further research is needed to understand the role of TW social networks in shaping HIV prevention knowledge, attitudes, practices, and PrEP uptake. TW social networks structure HIV prevention norms by influencing individual behavior, social and sexual interactions, and structural contexts. These networks are vital for information dissemination, with TW often preferring information from peers rather than medical institutions. Support and cohesion within TW networks can also empower individuals to overcome healthcare barriers and stigma, build alternative care access systems, and strengthen community advocacy, potentially impacting PrEP uptake and diffusion. Diffusion of innovations (DOI) theory highlights the role of social networks in adopting innovations. Key concepts include homophily, opinion leadership, and perceived innovation attributes. While DOI has guided HIV prevention efforts, prior unsuccessful attempts in Peru using community popular opinion leaders (C-POLs) raise questions about its applicability. The NIMH Collaborative HIV/STD prevention trial, a C-POL intervention, failed to demonstrate a difference in sexual risk practices and STI rates between the intervention and comparison groups. In Peru, both groups showed improved outcomes compared to baseline, suggesting that broad public health awareness campaigns, even without targeted opinion leaders, can positively impact behavior. This points to the need for careful adaptation of DOI concepts to specific cultural contexts. The C-POL study also highlighted a potential pitfall: assuming that providing information alone leads to behavioral change, potentially creating a knowledge, attitudes, and practice (KAP) gap. The KAP gap highlights that increased knowledge and changed attitudes do not necessarily translate into behavioral change. DOI theory, however, can be used to target interventions aimed at closing this gap by using opinion leaders to model behavioral change. Successful interventions in Haiti (using voodoo practitioners) and Nepal (using social modeling for vitamin A deficiency) illustrate this. This study uses DOI theory to understand PrEP uptake within TW social networks in Lima, Peru, focusing on key concepts like homophily and opinion leadership. Examining barriers to PrEP uptake through DOI’s five perceived attributes of an innovation (relative advantage, trialability, observability, complexity, and compatibility) can inform future interventions adapted to local contexts and leverage existing network structures.

The literature review extensively explores the disproportionate burden of HIV among transgender women (TW) globally and the challenges in implementing pre-exposure prophylaxis (PrEP) within this population. It highlights studies revealing low PrEP acceptability due to mistrust in medical institutions and prioritization of hormone therapy. The lack of public PrEP programs in countries like Peru and the high cost of accessing PrEP are also discussed. The review examines the established role of social networks in HIV prevention among men who have sex with men (MSM) and suggests the potential for similar influence within TW communities. Existing research emphasizes the preference of TW for receiving information from peer networks rather than formal healthcare settings. The role of social capital in empowering TW to overcome healthcare barriers and promote community advocacy is also considered. Further, the literature review analyzes the diffusion of innovations (DOI) theory and its application to HIV prevention interventions. It cites successful and unsuccessful examples of employing DOI theory, particularly focusing on the limitations of solely relying on information dissemination to achieve behavior change. The concept of the knowledge-attitude-practice (KAP) gap is introduced to emphasize the discrepancy between knowledge and actual practice. Studies demonstrating the successful integration of DOI with community-specific strategies to overcome this KAP gap are discussed, setting the stage for applying this theoretical framework to the context of PrEP uptake among TW in Lima, Peru.

This qualitative study, conducted in May 2018 in Lima, Peru, employed convenience sampling to recruit 20 transgender women (TW) aged 18 and older, self-identifying as HIV-negative or of unknown serostatus, and engaging in anal or oral sex within the past 12 months. Participants were recruited through a local TW community organization and screened for eligibility. One TW was under 18 and another had not engaged in the specified sexual activity, resulting in a final sample of 20. Data collection involved three components: (1) a brief demographic questionnaire; (2) a standardized social network interview; and (3) semistructured in-depth interviews. Two interviewers fluent in Spanish conducted the interviews; one was a TW community member, and the other was a cis-woman researcher experienced in qualitative HIV/STI research. Interviews took place in private locations. The interview guide, developed with input from TW community members and piloted with three TW, assessed relationship dynamics, support received, communication patterns, knowledge and attitudes toward condom use and PrEP, HIV/STI discussions, and how these influenced behavior. Thematic saturation guided recruitment, with interviews lasting 45-60 minutes. Participants received compensation for their time. Audio recordings were transcribed and checked for accuracy. Data analysis employed both quantitative and qualitative methods. Quantitative demographic and social network data were analyzed using Stata. Qualitative data from semistructured interviews were analyzed in Atlas.ti using immersion-crystallization, allowing researchers to immerse themselves in the data and reflect on emerging themes. A codebook was developed deductively (based on interview guide and literature) and refined inductively (adding and merging codes based on data). Two researchers independently identified major themes and assessed thematic saturation. One researcher then coded all transcripts line-by-line. The analysis was guided by DOI and KAP-gap theories.

The study revealed a median age of 26 among the 20 participants, all of whom engaged in sex work. Three-quarters were born outside Lima and had resided there for a median of five years. The majority (85%) lived in a "casa trans." While 85% had heard of PrEP, only 15% used it. The findings highlight the significant role of TW networks in sharing HIV prevention knowledge, with older TW often educating younger or newly arrived members about condom use and HIV/STI testing. Knowledge sharing extended beyond TW networks to family and partners, with respondents frequently acting as the primary source of HIV prevention information. The study observed universally positive attitudes toward routine HIV/STI testing, supported by regular access to screenings within TW networks. However, a disparity emerged between knowledge/attitudes and practices regarding condom use. Despite network support, consistent condom use was not common. Power imbalances in relationships with cis-male partners significantly influenced condom use, with respondents often accepting condomless sex to maintain relationships or due to economic coercion by clients. Some respondents experienced forced condom removal during sex. PrEP attitudes and practices were significantly shaped by limited PrEP access, primarily through research studies. This contributed to mistrust of the medical field and perpetuated beliefs that PrEP was unproven or experimental. Network members (including other TW, partners, and family) often shared these hesitant attitudes. Several structural barriers to PrEP access existed, including the time commitment required for research study participation, which conflicted with income-generating activities for many respondents. Lack of legal identification (DNI) further limited access to healthcare services for some. Conversely, social support from other TW who had positive PrEP experiences contributed to PrEP use in a few cases. Health promoters also played a role in encouraging some respondents to participate in PrEP studies.

The study reveals a persistent knowledge-attitude-practice (KAP) gap in HIV prevention among TW. While routine HIV/STI screening showed alignment between knowledge, attitudes, and practice, thanks to network support, condom use was significantly hampered by external factors such as power imbalances in relationships and economic pressures. PrEP uptake was low, largely due to limited access, misinformation, and resulting mistrust of the medical establishment within TW networks. The discussion uses the diffusion of innovations (DOI) framework to analyze these challenges. While certain PrEP attributes (trialability and observability) are less modifiable, improving perceived compatibility, relative advantage, and complexity is possible. The study suggests that PrEP's incompatibility with existing community values and norms contributes to hesitancy, highlighting the need for culturally sensitive outreach efforts engaging TW community leaders. Structural barriers, like limited access outside research studies, increase perceived complexity and decrease relative advantage. The discussion emphasizes the necessity of increased PrEP access, community-based campaigns, and potentially incentives to improve PrEP uptake. It also acknowledges the limitations of DOI theory, particularly its focus on individual agency and neglect of systemic barriers.

This study demonstrates the profound influence of TW social networks on HIV prevention knowledge, attitudes, and practices. PrEP outreach must target TW specifically, leveraging community relationships to enhance acceptability and access. Future interventions should use the DOI framework, incorporate TW input to ensure compatibility with community norms, and address structural barriers to PrEP access. Policy changes are crucial to expand PrEP availability and improve healthcare experiences for TW. Further research is needed to understand evolving PrEP awareness and attitudes within TW communities.

The study's findings may not be generalizable to TW in other regions of Peru or Latin America due to the specific social and cultural context of the sample. PrEP awareness, perceptions, and information dissemination patterns may have changed since data collection in 2018. The study focuses on the role of TW in knowledge sharing, but more research is needed on current PrEP information introduction and sharing within TW communities and how attitudes may have evolved.