CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

PrEP records, 66 (38%) were persistent on PrEP at 6-months, 58 (34%) were not persistent but retained in the study, and 49 (28%) were not persistent and lost to follow-up. Approximately half (94/173; 54%) were persistent at 3 months. 6-month persistence was higher for women (29/65; 45%) vs men (37/108; 34%) and for those aged ≥25 (43/103; 42%) vs <25 (23/70; 33%). Persistent HIV risk was common among those retained in the study, regardless of PrEP persistence. Among those with at ≥1 follow-up study visit (153/174; 88%), 25 (16%) reported having a partner living with HIV, and 58 (38%) reported exchanging sex for goods, money or favors in the preceding month. Among the 136/174 (78%) with ≥1 follow-up Ct/Ng test, 32 (24%) had ≥1 incident STI (Ct: 15; Ng: 7, Ct and Ng: 10). Conclusion: Despite ongoing HIV risk, including frequent incident STIs in a short follow-up period, PrEP persistence among a cohort of persons initiating PrEP from an STI clinic in Malawi was poor. Persistence was particularly low among men, who accounted for nearly two-thirds of the study population. Strategies to address barriers to persistent PrEP use, especially for the relatively understudied population of heterosexual men in SSA, are urgently needed.

program and moderate adherence overall. Since these programs serve people with different harm reduction preferences, further research is needed to explore how to effectively integrate PrEP into community- and facility-based programs. 1190 Modeling the Potential Impact of Scaling Up Event-Driven PrEP Among Gay, Bisexual, and Other MSM Christina Chandra 1 , Kevin Maloney 2 , Karen W. Hoover 3 , Samuel M. Jenness 1 1 Emory University, Atlanta, GA, USA, 2 Georgia State University, Atlanta, GA, USA, 3 Centers for Disease Control and Prevention, Atlanta, GA, USA Background: Oral HIV preexposure prophylaxis (PrEP) is effective at preventing HIV acquisition among gay, bisexual, and other men who have sex with men (MSM). A small proportion of PrEP users in the United States practice event-driven PrEP (EDP), despite high interest in and willingness for the dosing regimen. EDP has also been found to be useful for daily PrEP users with low adherence. However, the population-level HIV impact of EDP given real-world empirical data on time-varying adherence is unknown. Methods: We extended an existing network-based mathematical HIV transmission model for MSM to allow initiation of EDP with varying adherence across sex acts. EDP is implemented as the 2-1-1 dosing schedule: 2 pills on the day of sex, 1 pill a day after, and 1 pill 2 days after. Daily and EDP users may switch regimens. Adherence and efficacy of EDP were parameterized using data from IPERGAY, HPTN 067/ADAPT, and AMPrEP. We simulated counterfactual scenarios over 10 years, including incremental increases in EDP initiation rates among MSM with daily PrEP indications who do not start daily PrEP, expanding EDP eligibility to any MSM sexually active in the last 6 months, and targeting EDP eligibility to daily PrEP discontinuers with low adherence. These scenarios were compared to a reference scenario with only daily PrEP. Models were calibrated to HIV prevalence and PrEP coverage levels among MSM in Atlanta, Georgia. Results: In the reference scenario, HIV incidence was 0.38 per 100 person-years. The percent of infections averted (PIA) was 1.0% when MSM were equally likely to start EDP as daily PrEP with the same indications and 2.2% when MSM were 1.5 times as likely to start EDP. Expanding eligibility for EDP to any sexually active MSM yielded a PIA of 7.5%, while tailoring eligibility to daily PrEP discontinuers with low adherence led to 1.4% more infections. 373,726 pills were needed to prevent an HIV infection when EDP indications were the same as daily PrEP, compared to 193,567 pills with expanded EDP eligibility. Conclusion: EDP yielded modest population-level reductions in HIV incidence and infections averted over 10 years given the non-inferiority of EDP to daily PrEP. Providing EDP with a low indication threshold (any sexually active MSM) provided greater benefits than targeted provision of EDP to MSM with daily PrEP adherence challenges. In terms of medication efficiency, expanding EDP among MSM with recent sex reduced overall pill burden in the population while maintaining PrEP effectiveness. 1191 PrEP Persistence and Ongoing HIV Risk Among Patients Initiating PrEP at an Urban Malawi STI Clinic Sarah E Rutstein 1 , Jane Chen 1 , Esther Mathiya 2 , Griffin J. Bell 1 , Beatrice Ndalama 2 , Tapiwa Munthali 2 , Naomi Nyirenda 2 , Naomi Bonongwe 2 , Claire Pedersen 2 , Edward Jere 2 , Mina Hosseinipour 1 , Zakaliah Mpande 3 , Irving F. Hoffman 1 , Mitch Matoga 2 , for the ePrEP Study Team 1 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA, 2 University of North Carolina Project– Malawi, Lilongwe, Malawi, 3 Lighthouse Trust, Lilongwe, Malawi Background: Persons presenting with sexually transmitted infections (STI) are a priority group for HIV prevention, including biomedical pre-exposure prophylaxis (PrEP). Longitudinal risk and persistent use of oral PrEP among STI patients in sub-Saharan Africa (SSA) has not been well characterized. Methods: We enrolled men and women ≥15 years presenting to an urban STI clinic who were eligible for and initiated on PrEP according to Malawi PrEP guidelines. All PrEP care was provided by Ministry of Health staff. Participants were tested for Chlamydia trachomatis (Ct), and Neisseria gonorrhoeae (Ng) at enrollment, month 3, and month 6, and completed behavioral surveys. PrEP persistence was derived from PrEP record review, defined as no >7 days without pills based on visit date, pills distributed, and self-reported missed pills. Results: We enrolled 174 participants initiating PrEP between March-December 2022. Nearly two-thirds were male (109/174; 63%), and 70/174 (40%) were <25 years. In the month preceding PrEP initiation, 23/174 (13%) reported having a partner living with HIV and 69/174 (40%) had exchanged sex for goods, money, or favors. Four (4%) men endorsed ever having anal sex. Of 173 with linked

Poster Abstracts

1192 PrEP Knowledge and Use: Results From the Zambia Population-Based HIV Impact Assessment 2021 Nzali G Kancheya 1 , Brian Muyunda 1 , Omega Chituwo 1 , Megumi Itoh 1 , Bupe Musonda 2 , Mumbi Chola 3 , Megan Bronson 4 1 Centers for Disease Control and Prevention, Lusaka, Zambia, 2 Government of Zambia Ministry of Health, Lusaka, Zambia, 3 University of Maryland, Baltimore, MD, USA, 4 Centers for Disease Control and Prevention, Atlanta, GA, USA Background: Pre-exposure prophylaxis (PrEP) taken daily has been shown to be effective prevention against HIV acquisition and has been recommended by WHO for people at substantial risk for HIV since 2015. Zambia has been implementing the PrEP program since 2017 and rolled it out nationwide in 2018. Methods: We analyzed data from the 2021 Zambia Population Based HIV Impact Assessment (ZAMPHIA). We used descriptive analysis (with chi-square test) to analyze demographic and behavioral characteristics of PrEP knowledge and PrEP use, and a weighted multivariable logistic regression model to identify key predictors of PrEP use among all participants. All results were weighted to account for complex survey design. Results: Among 22,183 participants aged 15+ year who answered the PrEP questions, 21.2% (95% CI: 20.3- 22.2) reported ever having heard of PrEP: 18.9% (95% CI: 17.6-20.2) among men and 23.5% (95% CI: 22.3-24.8) among women. Within age groups 17.5% (95% CI 16.1-18.9) of young adults aged 15 to 24 years and 17.2% (95% CI: 15.8-18.7) of those aged 45+ years had ever heard of PrEP. Other characteristics associated with having ever heard of PrEP were being married (22.1% [95% CI: 20.9- 23.3]), living in urban areas (30.3% [95% CI:28.5 32.1]) and having more than a secondary education (56.7% [95% CI:52.8-60.4]). Of those who have ever heard of PrEP, 3.9% (95% CI: 3.2- 4.8) reported ever using PrEP. PrEP use was highest among those who reported having a sexual partner who is HIV positive 16.5% [95% CI: 12.3- 21.7]). Those who reported a HIV positive sexual partner were more likely to report ever having used PrEP compared to those who did not know the HIV status of their partner (aOR 5.84 [95% CI: 3.27-10.41]; P<0.001). Conclusion: Although PrEP has been available country wide since 2018, just over one-fifth of adults age 15+ years were aware of PrEP. This is of concern particularly among young adults aged 15-24 who have the highest incidence of HIV as seen in ZAMPHIA. These results can guide the Ministry of Health to target the dissemination of PrEP information to populations with low knowledge of PrEP, including men, those aged 45+ years, living rural areas, and with lower

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