BackgroundMen who have sex with men (MSM) receiving HIV pre-exposure prophylaxis (PrEP) are often exposed to repeated antimicrobials due to a high burden of sexually transmitted infections (STIs). These factors may contribute to the selection of antimicrobial resistant bacteria within the intestinal microbiota. This study aimed to investigate the prevalence of antimicrobial resistance (AMR) among Enterobacteriaceae isolated from rectal swabs of MSM receiving PrEP and to assess possible associations with behavioral and PrEP-related variables.MethodsIn this cross-sectional study, rectal swabs were collected from MSM receiving PrEP who had no gastrointestinal symptoms and were attending the Infectious Diseases Clinic of the 'IRCCS Azienda Ospedaliero-Universitaria di Bologna' (Italy) for routine STI screening. The same anorectal specimens were used for culture-based isolation, and antimicrobial susceptibility testing of Enterobacteriaceae. Behavioral and clinical data were collected through structured questionnaires.ResultsA total of 126 Enterobacteriaceae isolates, predominantly Escherichia coli (n = 79; 63%) and Klebsiella spp. (n = 35; 28%), were recovered from 89 of the 92 subjects enrolled. Nearly three-quarters of participants reported antimicrobial use in the previous 12 months, and almost one quarter in the month preceding enrolment. Overall, 40% and 39% of participants reported Chlamydia trachomatis and Neisseria gonorrhoeae, respectively, within the previous two years. Considering all Enterobacteriaceae isolates, resistance to sulfamethoxazole/trimethoprim was the most frequent, followed by ciprofloxacin; resistance to third-generation cephalosporins ranged from 5% to 8%. Resistance to piperacillin/tazobactam was rare (2%), and no carbapenem-resistant isolates were detected. Although not statistically significant, participants reporting recent antibiotic use were more likely to harbor resistant strains across all antimicrobial classes.ConclusionsRepeated antimicrobial exposure for STI management may shape intestinal resistance patterns of Enterobacteriaceae among MSM receiving PrEP. Our findings support the need for continued AMR monitoring and targeted antimicrobial stewardship interventions in this population.

The For the Assessment of Individualized Risk (FAIR) framework, introduced by NHS Blood and Transplant (NHSBT) in 2021, aims to reduce stigma and improve equity in blood donor selection, particularly for gay, bisexual and other men who have sex with men (GBMSM). While pre-exposure prophylaxis (PrEP) is highly effective at preventing sexual transmission of human immunodeficiency virus, its declared use excludes individuals from blood donation. This study examined PrEP use among male blood donors with current or past syphilis in England to evaluate guideline compliance and implications for blood safety. Residual plasma samples from syphilis-positive male blood donors collected in 2023 were tested for PrEP. These data were combined with two previous studies of syphilis-positive donors conducted between July 2018 and June 2024, incorporating demographics and reported PrEP use. The rate of syphilis-positive blood donations increased from 4.09 to 10.32 per 100,000 donations between 2018 and 2024 (p = 0.048, Mann-Kendall trend test) with a rising proportion of past syphilis cases attributed to GBMSM (18%-37%; p = 0.004, Fisher's test, p = 0.001 Mann-Kendall test); 7.1% of syphilis-positive blood samples from male blood donors tested positive for PrEP in 2023, indicating frequent non-compliance with donation guidelines. Persistent PrEP use among syphilis-positive donors since 2018 suggests gaps in donor education regarding eligibility. Targeted public health interventions, particularly for younger GBMSM, are needed to strengthen sexual health education, PrEP messaging and awareness of donation criteria. Further research into other infections associated with high-risk sexual behaviour is warranted.

ABSTRACT We assessed the correlates of willingness to use PrEP among young people (YP) impacted by HIV in Uganda. This cross-sectional study included 905 YP aged 18–21 years, orphaned to AIDS and participating in a longitudinal study in Uganda. Willingness to use PrEP, the primary outcome, was measured using a hypothetical scenario. “If PrEP were safe, effective, free, and used by few people around you, how likely would you be willing to use it?” Independent variables included sociodemographic characteristics, perceived HIV risk, PrEP stigma, barriers to PrEP use, and social support. Multilevel mixed-effects logistic regression was used to examine the relationship between willingness to use PrEP and the independent variables, adjusting for clustering. 74.7% of participants reported willingness to use PrEP. Older age and perceived risk of HIV were associated with a higher likelihood of willingness to use PrEP (aOR = 1.10; 95% CI = 1.01, 1.21 and aOR = 1.65; 95% CI = 1.26, 2.17 respectively). Perceived PrEP stigma was associated with lower willingness (aOR = 0.30; 95% CI = 0.21, 0.42). YP impacted by HIV, show high willingness to use PrEP, influenced by age, risk perception, and stigma.

HIV pre-exposure prophylaxis (PrEP) is proven effective for HIV prevention and recommended for individuals at ongoing and high risk of HIV, including gay, bisexual, and other men who have sex with men (GBMSM) and people who inject drugs (PWID). We used existing national survey data to measure PrEP need in both populations and calculate percentages of use among those meeting indications within each group. We conducted a secondary data analysis of nationally representative data to estimate the percentage of GBMSM and PWID meeting PrEP indications based on 2017 Canadian guidelines. We applied these percentages to recent population size estimates for both groups to estimate the number of people having PrEP indications in each group. Where available, we also used survey data to determine the percentage of people with indications who were not taking PrEP at the time of the survey. An estimated 24.1% (95% CI 13.3-39.7%) or 99,300 (95% CI 54,800-163,600) of GBMSM had PrEP indications in Canada as of 2021. The corresponding percentage and number for PWID were 22.3% (20.8-22.8%) and 22,400 (20,900-23,900). Two-thirds of GBMSM participants (Sex Now 2019 and 2021) who had PrEP indications were not taking PrEP at the time of the surveys. None of the participants with PrEP indication in the Tracks survey (2017-2019) among PWID reported PrEP use. In Canada, the estimated number of people with PrEP indications among GBMSM and PWID far exceeded documented levels of use. Uptake of PrEP was lower among PWID compared to GBMSM. Efforts to improve PrEP access and uptake could help reduce HIV transmission in Canada.

Although oral pre-exposure prophylaxis (PrEP) has been instrumental in decreasing HIV incidence, its daily dosing regimen poses adherence challenges. Using an agent-based network model informed by empirical data, we simulate the impact of introducing long-acting injectable (LAI) PrEP among young Black men who have sex with men (YBMSM) in Los Angeles County, a group disproportionately affected by HIV. Computer simulations using an agent-based network model. We modeled HIV transmission among YBMSM over 10 years under scenarios varying the proportion of PrEP users opting for LAI instead of oral medications and adherence levels to LAI retention. The model was calibrated with empirical data and included dynamic sexual networks, HIV progression, and biomedical interventions. Modeling showed that LAI PrEP substantially reduced HIV incidence and prevalence over 10 years compared with oral PrEP alone. Scenarios with LAI retention (ie, continued use across bimonthly dosing cycles) rates of 60% or higher resulted in reductions comparable with or exceeding those achieved by oral PrEP, with up to a 45% decrease in HIV incidence observed when all PrEP users switched to LAI and retention reached 85%. Long-acting injectable PrEP offers significant potential to advance HIV prevention efforts among YBMSM by addressing adherence challenges inherent to oral PrEP. Integrating LAI into public health initiatives may yield substantial reductions in HIV incidence, contributing to ending the HIV epidemic among this high-priority population.

175. Implementation of an HIV Pre-Exposure Prophylaxis (PrEP) Toolkit for Youth-Serving Primary Care Providers

Introduction The introduction of new pre-exposure prophylaxis (PrEP) methods presents an opportunity to expand choice and better integrate HIV prevention and broader sexual and reproductive health (SRH) services. Integrating HIV prevention services, including PrEP, and SRH services presents an opportunity to improve healthcare access and outcomes. However, implementation within real-world healthcare settings requires an understanding of both enablers and barriers from the perspective of healthcare providers (HCPs). Methods A qualitative descriptive study was conducted using in-depth interviews (IDIs) to describe the integration of PrEP and SRH services, drawing on the perspectives of HCPs. Thirty-four HCPs were purposively sampled and interviewed between October and November 2024 across four South African locations: eThekwini, Gqeberha, Mthatha, and Tshwane. Audio recordings were transcribed, translated, and analysed using inductive thematic analysis with NVIVO 14 software. Results Key benefits of service integration expressed by HCPs included increased continuity of care with the same HCP, convenience, and a higher uptake of SRH services, such as contraception and sexually transmitted infection (STI) screening and management. Facilitators included integrated education and awareness, flexibility in alignment of appointment schedules, and positive staff attitude. Challenges and barriers included misalignment between injectable PrEP and injectable contraceptive visit schedules and infrastructural limitations within some public health facilities. Conclusions Successful integration requires adaptable systems, responsive scheduling, functional infrastructure, and positive staff attitude. To improve uptake and continuity of SRH services, health systems should be flexible and provide holistic services that align with client needs.

Attitudes toward and use of pre-exposure prophylaxis (PrEP) by coupled sexual minority men (SMM) may be influenced by exposure to intimate partner violence (IPV) and sexual agreements regarding non-monogamy. We examined IPV (victimization and perpetration) persistence over 12months and its association with HIV prevention behaviors and attitudes among 271 coupled, HIV-negative SMM, and the moderating role of sexual agreements. The sample had diverse race/ethnicity (64% were non-White) and was from across all regions of the USA. Participants completed a self-administered, Web-based survey at baseline, 6months, and 12months, and reported having the same main partner throughout. Repeated measures regression analysis showed that the level of IPV persistence was unrelated to PrEP use; however, persistent (i.e., present at all three assessments) IPV victimization and perpetration both predicted lower perceived partner support for PrEP use among those not using PrEP, as well as greater PrEP stigma. Persistent IPV victimization and perpetration were both predictive of more frequent HIV testing. The presence of a sexual agreement for non-monogamy (i.e., sex outside the primary relationship), which was a significant independent predictor of more HIV testing and PrEP use, moderated the relationships between IPV and HIV testing and partner support for PrEP, albeit in mixed ways: In non-monogamous relationships, persistent IPV victimization and perpetration were both associated with less HIV testing, but greater perceived partner support for PrEP use. In one of the first longitudinal studies of IPV and HIV prevention among SMM, these findings suggest a complex and nuanced influence of IPV on HIV prevention behaviors and attitudes and the key role that open communication and agreements related to extradyadic sex partners may have for HIV prevention among coupled SMM.

Latino men who have sex with men (MSM) in the United States experience significant HIV disparities, exacerbated by mental health and substance use (MH/SU) concerns. Although evidence-based clinical interventions, such as pre-exposure prophylaxis (PrEP) and MH/SU treatment, can prevent HIV and mitigate MH/SU adverse outcomes, their reach to Latino MSM remain suboptimal. This gap underscores the need for adjunctive interventions and implementation strategies that improve PrEP and MH/SU treatment reach. SOMOS Alianza (San Juan, Orlando, Miami Organizational Strategic Alliance) is a research-practice network spanning three Ending the HIV Epidemic (EHE) jurisdictions. HIV organizations in SOMOS Alianza leverage their expertise in serving Latino MSM to develop and use adjunctive interventions and implementation strategies to improve PrEP and MH/SU treatment reach within their communities. These locally developed interventions and strategies could be scaled across other HIV organizations to meet U.S. EHE goals. In Aim 1, we will characterize and assess the degree to which existing adjunctive interventions and strategies used by local organizations align with the existing evidence base. We will combine Rapid Assessment Procedure-Informed Clinical Ethnography and "reverse" implementation mapping to evaluate these interventions and strategies. In Aim 2, we will apply user-centered design principles to develop an online Dashboard featuring interventions and strategies identified in Aim 1. Finally, in Aim 3 we will assess the Dashboard's usability and impact at the organizational level across EHE jurisdictions. Using baseline and 12-month follow-up assessments, we will evaluate outcomes quantitatively and qualitatively, and results will be used to refine the Dashboard for public use. This study will go beyond traditional research-to-practice models by identifying and scaling up existing adjunctive interventions and implementation strategies, addressing gaps in implementation science and ultimately improving health outcomes for Latino MSM. Expected outcomes include identifying contextually appropriate and feasible approaches to improve PrEP and MH/SU treatment reach to Latino MSM, developing a scalable Dashboard for dissemination, and creating a generalizable model for implementation, and advancing public health goals aligned with EHE priorities.

Epidemiological and economic impact of pre-exposure prophylaxis with targeted immunotherapies for COVID-19 among immunosuppressed patients in Argentina.

ABSTRACT Cisgender women account for approximately 20% of new HIV diagnoses in the U.S., yet of those indicated for pre-exposure prophylaxis (PrEP) uptake is only 10%. Cisgender women are amenable to PrEP; however, clinicians encounter individual and interpersonal barriers to prescriptions. This research examines clinicians’ decision-making processes regarding PrEP provision for cisgender women. Semi-structured individual interviews were conducted with clinicians working with cisgender women in the U.S. to explore their decision-making processes for PrEP prescription and were presented with a vignette of a hypothetical patient. Clinicians were asked how they would assess their eligibility for PrEP and their clinical recommendations. Eighteen clinicians were interviewed. The majority reported at least some familiarity with PrEP. The majority were practicing clinicians trained as OB/GYNs, followed by Primary Care/Family/Internal Medicine. Clinicians frequently report their PrEP recommendations rely on the patient’s overall risk and ability to use condoms. Clinicians’ decision-making processes often follow a linear pathway through (1) the assessment of HIV risk, (2) STI testing, (3) condom counseling, and (4) PrEP counseling and provision. Despite medical guidelines recommending PrEP to all sexually active patients, clinicians rely on condoms as the primary prevention method and continue to assess the utility of PrEP through a risk-focused lens.

Pre-exposure prophylaxis (PrEP) is the cornerstone of HIV prevention in the United States, yet uptake remains low among bisexual men compared to gay men. Theory-driven communication interventions have promise for addressing this disparity. Prior research among gay and bisexual men has shown that the Reasoned Action Approach (RAA) can predict PrEP intentions through attitudes, norms, and perceived behavioral control, while other studies highlight the influence of sexual identity-related stressors on prevention behaviors. However, bisexual men remain underrepresented in this work. This study sought to address this gap by exploring modifiable socio-cultural influences on bisexual men's PrEP use that can inform the development of PrEP promotion messages. Through an online survey of N = 276 US bisexual men, this study examined the relative impact of RAA factors (e.g., attitudes, perceived norms, and control beliefs) and identity-related stressors (e.g., concealment, masculine consciousness, and identity conflict) on intentions to use PrEP. The results revealed that, in contrast to previous work, only experiential attitudes toward PrEP (e.g., worry over HIV risk) were significantly associated with intentions, while instrumental attitudes, norms, and control beliefs were not. Regarding identity-related stressors, concealment from family was negatively associated with intentions, but masculine consciousness and identity conflict were not. Findings suggest that bisexual men's PrEP decisions may be shaped less by the cognitive predictors and more by affective and concealment-related processes. The results underscore the risk of generalizing findings from studies of gay men to bisexual men and highlight the need for more research to understand bisexual men's PrEP use motivations.

Human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) is a key component of a comprehensive approach to ending the HIV pandemic. Still, uptake is low for individuals most likely to derive the greatest benefit, including underrepresented populations in the Southern United States (U.S). We initiated a rapid PrEP initiation program to increase PrEP uptake. We performed a retrospective study analyzing demographic, clinical characteristics, and rates of PrEP follow-up for individuals started on rapid PrEP at the Durham County Department of Public Health in Durham, North Carolina, U.S. We also evaluated what factors were associated with continuation of PrEP and subsequent PrEP follow-up. Overall, rates of PrEP continuation were low at 42% at 3 months. PrEP continuation was positively associated with follow-up at one of the academic medical centers in our area. Almost half of the individuals who failed to make their 3-month PrEP appointment were subsequently seen back in our Sexual Health Clinic, and these individuals were more likely to identify as female and lack health insurance. Overall, PrEP discontinuation rates were high at 3 months, likely in part due to high rates of individuals lacking health insurance in our setting. Half of the individuals who discontinued PrEP returned to our health department for sexual health services, suggesting that while offering PrEP at local health departments in the U.S. may be an important entry point for PrEP care, providing the full spectrum of PrEP care at local public health departments may improve retention on PrEP.

No US Food and Drug Administration (FDA)-approved prophylaxis is currently available for Acute Radiation Syndrome (ARS), which remains a significant threat to military and civilian populations. In this study, we investigated Vasculotide (VT), a Tie2 receptor agonist mimic, as a novel pre-exposure prophylaxis designed to stabilize the vascular endothelium, one of primary targets of radiation-induced damage. To evaluate its efficacy, female B6D2F1/J mice were exposed to 9.5 Gy total body irradiation (TBI), with VT administered subcutaneously at 12 and 2 h prior to exposure. Assessments included 30-day survival, biomarkers of vascular injury, proinflammatory cytokine/chemokine profiling, and evaluation of hematopoietic (H) and gastrointestinal (GI) recovery. Our findings demonstrate that VT significantly increased 30-day survival in a dose-dependent manner, achieving a 30% survival advantage at the 20 μg/kg dose. Furthermore, VT provided robust protection against radiation-induced vascular activation and injury, effectively alleviating damage to the bone marrow (BM) and GI tract. Taken together, these results identify VT as a promising prophylactic countermeasure for ARS. By targeting the Tie2 pathway to preserve vascular integrity, VT addresses a critical gap in medical countermeasures, offering a viable strategy to enhance survival and accelerate multi-organ recovery in radiological mass-casualty scenarios.

BackgroundHealth Frontiers in Tijuana, a binational collaboration between Californian and Mexican universities, cares for housing-insecure patients that suffer from inequitable access to health care in urban Tijuana. This study aimed to identify the prevalence and sociodemographic correlates of HIV testing in our catchment area, as well as the prevalence and correlates of HIV status among those tested.MethodsAnalysis was performed on electronic medical record data from clinic visits during 2022-2024. Demographics and diagnostic categories were tabulated, and logistic regression was performed to determine predictors of HIV status.Results2390 attendances by 1158 patients were analysed. Among 180 patients tested for HIV during this time period, 18(10%; 95% CI: 6%-15%) had a new diagnosis of HIV, which is up to 50 times greater than the national 0.19% prevalence of people living with HIV in Mexico. Women (aOR: 3.5, 95% CI: 1.8-6.7), people who use drugs (aOR: 5.2, 95% CI: 2.1-13.1), and people with another sexually transmitted infection (aOR: 3.3, 95% CI: 1.6-6.7) had significantly greater risk for HIV.ConclusionsOur data identified a niche population in Tijuana with substantially higher risk for HIV acquisition and transmission compared to the general public. This suggests a need for greater accessibility of HIV rapid testing in this group, as well as enhanced linkage to care for HIV pre-exposure prophylaxis candidates.

ABSTRACT It is unclear whether online partner-seeking via (geo)social networking and dating websites or applications (“apps”) is associated with engagement in condomless anal sex (CAS) among MSM (men who have sex with men). Previous studies present mixed findings revealing either positive, or negative, or no associations between online partner-seeking and CAS among MSM, indicating a need for additional research. This cross-sectional survey of young adult MSM residing in 15 Central Kentucky counties, USA (n = 217) provided demographic, behavioral, and relationship data about male or transgender partners (n = 548), with whom respondents had recent (past 6 months) anal sex. We used multivariable generalized linear mixed effects modeling to compare engagement in CAS (i.e. used condoms only sometimes or never) between app-facilitated and non-app-facilitated relationships. Our analysis revealed most relationships involved CAS (72%), but there were no differences between app-facilitated and non-app-facilitated partnerships. Increasing age of nominated partners (especially within non-app-facilitated relationships); White, non-Hispanic race-ethnicity of respondents; daily communication with nominated partners; and respondents’ lifetime history of sex with individuals living with HIV were independently associated with higher odds of CAS. Our findings showed app-facilitated relationships were no “riskier” in terms of CAS than other relationships. A large proportion of partnerships reporting CAS urges for diverse strategies designed and implemented via apps and more traditional venue outreach to promote (self-)testing, consistent condom use, and pre-exposure prophylaxis (PrEP) uptake.

Using an established pharmacokinetic/pharmacodynamic tissue model of tenofovir disoproxil fumarate/emtricitabine for HIV pre-exposure prophylaxis (PrEP), we predict that adding a fourth day of dosing to the 3-day IPERGAY on-demand PrEP regimen (currently approved for men/transgender women who have sex with men) will be efficacious for on-demand dosing in cisgender women.

Exploring Typology and Determinants of Pre-exposure Prophylaxis Adherence Trajectories Among Men Who Have Sex with Men in Western China

Amebiasis, caused by Entamoeba histolytica, has emerged as a sexually transmitted enteric infection among men who have sex with men (MSM) and people with HIV (PWH) in developed countries. While previous surveillance studies in Taiwan among PWH showed ongoing transmission, investigation on E. histolytica infection among non-HIV MSM using newer diagnostic methods and ELISA-IgG seroprevalence surveys is lacking. From March 2024 to February 2025, we conducted a cross-sectional study during an LGBTQ + Pride event and at a tertiary medical center in southern Taiwan. MSM participants were recruited during anonymous HIV and syphilis testing, or during follow-up visits for HIV pre-exposure prophylaxis or antiretroviral therapy. We collected serum samples for E. histolytica ELISA IgG and self-collected rectal swabs for molecular diagnosis. DNA extraction was performed using an optimized protocol. A novel quantitative PCR assay utilizing specific primers and a double-quencher probe was developed to enhance detection specificity and reduce background noise. Among 139 non-HIV MSM participants, 11 individuals tested positive for E. histolytica IgG, yielding a seroprevalence of 7.9%. Molecular testing by rectal swab quantitative PCR identified two positive cases (1.4%). Of the two positive cases, one developed diarrhea just before examination, while the other remained asymptomatic. The novel PCR primer probe set detected E. histolytica DNA from rectal swab samples with high specificity. The present study investigated E. histolytica infection among non-HIV MSM in Taiwan using ELISA IgG and novel molecular diagnostic methods. The seroprevalence of 7.9% suggests ongoing transmission in this population. The optimized self-collected rectal swab protocol combined with the novel PCR assay provides a practical surveillance tool. Further investigation and targeted prevention strategies are warranted.

The postpartum period presents an opportunity to provide pre-exposure prophylaxis (PrEP) to cisgender women who may benefit. As patients rely on providers to provide PrEP education and frame relevance, barriers and facilitators to providers' initiating sexual health and HIV prevention discussions as a part of postpartum care must be identified to support implementation. Semi-structured interviews with 33 postpartum providers (10 residents, 6 advanced practice providers, 6 attendings, and 11 registered nurses) were conducted utilizing social cognitive theory as a framework. Providers expected that their postpartum patients would find HIV prevention discussions uncomfortable, not personally relevant, and/or stigmatizing. Providers identified normalization of PrEP discussions, universalization of PrEP discussions and tailoring conversations to meet their patients' needs as strategies to support comfort and confidence in discussing PrEP with their patients. Providers who believed that obstetrical care extended beyond an exclusive focus on pregnancy identified the postpartum context as an opportunity to provide PrEP education and other sexual health services. Providers identified environmental barriers, including frequent interruptions, language barriers, and lack of time for discussions. Nurses demonstrated receptivity to discussing PrEP, suggesting task shifting as a potential implementation strategy for integration of PrEP into postpartum care. Findings indicate that to support integration of PrEP into postpartum care, providers must be (1) educated on patient preferences surrounding sexual health discussions to align their expectations, (2) empowered with communication strategies that support normalization and tailoring of universally delivered PrEP education, and (3) supported in providing postpartum care that is comprehensive and includes education about HIV prevention.