CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

(n=2,706; 35%) and half of men (n=6,216; 52.9%) reported consistent condom use with these partners. Both male and female self-reported never-users were more likely to be older and in non-marital monogamous relationships of significantly longer duration. HIV incidence rates were similar among men who reported never using condoms (0.9/100 pys; 95%CI 0.39-1.93), always using condoms (0.9/100 pys, 95%CI: 0.64-1.16), and men reporting inconsistent use (1.2/100 pys, 95%CI: 0.88-1.60). Among women, incidence was lowest among those reporting never using condoms (1.4/100 pys; 95%CI: 0.78-2.56) followed by always-users (2.0/100 pys: 95%CI: 1.40-2.91), and highest among inconsistent users (2.8/100 pys, 95%CI: 2.17-3.65). Conclusion: In this study, self-reported never-users had lower or similar incidence compared to self-reported always-users, suggesting self-reported condom use is not a robust indicator of HIV risk. Reviewing self-reported condom use as a PrEP eligibility criterion might improve PrEP accessibility for those with increased HIV risk. 1029 An HIV-1 Risk Assessment Tool for Women in 15 African Countries: A Machine Learning Approach Nora E Rosenberg 1 , Bonnie E. Shook-Sa 1 , Amber M. Young 1 , Yating Zou 1 , Lynda Stranix-Chibanda 2 , Marcel Yotebieng 3 , Nadia Sam-Agudu 4 , Sam Phiri 5 , Linda Gail Bekker 6 , Sizulu Moyo 7 , Manhattan Charurat 8 , Jessica E. Justman 9 , Michael Hudgens 1 , Benjamin H. Chi 1 1 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA, 2 University of Zimbabwe, Harare, Zimbabwe, 3 Albert Einstein College of Medicine, Bronx, NY, USA, 4 University of Minnesota, Minneapolis, MN, USA, 5 Partners in Hope, Lilongwe, Malawi, 6 University of Cape Town, Cape Town, South Africa, 7 Human Sciences Research Council, Pretoria, South Africa, 8 University of Maryland, Baltimore, MD, USA, 9 Columbia University, New York, NY, USA Background: Women in Africa disproportionately acquire HIV-1. Understanding which women are most likely to acquire HIV-1 can guide focused prevention, including promotion of pre-exposure prophylaxis (PrEP). We used machine learning to develop a risk assessment tool to identify women most likely to acquire HIV-1 across African countries and to estimate HIV-1 infections averted with focused PrEP. Methods: Nationally representative data were collected from 2015-2019 from 15 population-based household surveys. This analysis included women aged 15-49 years who tested HIV-1 sero-negative or had recent HIV-1, characterized by HIV limiting antigen avidity enzyme immunoassay, HIV-1 viral load, and detection of antiretroviral drugs in their survey blood samples. Least absolute shrinkage and selection operator regression models were fit with 28 variables to predict recent HIV-1. Models were trained on the full population and internally validated using five-fold cross validation. Performance was evaluated using area under the receiver-operating-characteristic curve (AUC). Sensitivity, specificity, and potential cases averted were estimated, assuming perfect PrEP adherence among all women at key HIV-incidence thresholds. Results: Among 209,012 participants 248 had recent HIV-1 infection, representing 118 million women and 402,000 (95% CI: 309,000-495,000) new annual infections. Only two variables were retained: living in a subnational area with high HIV-1 viremia prevalence and having a sexual partner living outside the home. Overall AUC was 0·80 (95% CI: 0·76-0·84); cross-validated AUC was 0·79 (95% CI: 0·74-0·84). At one key HIV-1 incidence threshold (0.4 per 100 person-years), sensitivity was 67.7% and specificity was 78%. If the 26.1 million women at highest risk for HIV-1 perfectly adhered to PrEP, up to 264,000 cases could be averted. Conclusion: HIV-1 acquisition is not evenly distributed, with two thirds of infections occurring among a small fraction of women. This predictive, generalizable, and parsimonious tool has the potential to guide high-impact PrEP delivery.

weighting we explored HIV prevalence trends. We estimated HIV incidence pooled for 2011-2017 (since patterns were similar across years), and for 2021-2023, based on HIV prevalence rises with age ("prevalence to incidence method"). In 2021, we also estimated HIV incidence using recent infections ("RITA method", MDRI 130 days, false recency 0.2%). In addition, the HIV synthesis model was calibrated to data from Zimbabwe. Results: HIV prevalence in 2021-23 was 16.9% lower than in previous surveys pooled (2011-2017, 4314/7964, RDS-II prevalence 54.2%; 2021-23, 2220/5954, 37.3%, Figure Panel A). HIV prevalence fell in 11/13 towns and in both cities with repeated surveys, between 2017 and 2021/2023, by an average of 8.5% (Figure Panel B). HIV incidence ("prevalence to incidence method") was similar in both 2011-2017 and 2021-23, estimated at 4.4/100pyar. HIV incidence in 2021 ("RITA method") was estimated at 1.9/100pyar (17 recent infections, 1396 long term positive, 2107 HIV negative samples). Modelled HIV incidence was higher than the empirical estimates, but fell from 12.1/100pyar (2015) to 4.5/10 pyar (2021). Conclusion: Using population-based sampling we show a large reduction in HIV prevalence over time among FSW in Zimbabwe. Trends in incidence are harder to estimate, but incidence may be declining, partly driven by improved treatment coverage among men. PHIA data suggest that the proportion of males aged 15-49 living with HIV who had suppressed viral load increased from 48.9% (2015/16) to 68.1% (2020). HIV incidence remains unacceptably high among FSW. Persistence and innovation in HIV prevention for FSW are needed.

Poster Abstracts

1028 HIV Incidence by Self-Reported Frequency of Condom Use: A Population Based Cohort Study in Uganda Victor Popoola 1 , Fred Nalugoda 2 , Caitlin E. Kennedy 3 , Godfrey Kigozi 2 , Gertrude Nakigozi 2 , Steven J. Reynolds 4 , Aaron A. R. Tobian 1 , Victor Ssempijja 5 , Justin Lessler 6 , Arthur G. Fitzmaurice 7 , Maria J. Wawer 3 , Larry W. Chang 8 , Ronald M. Galiwango 2 , Joseph Kagaayi 9 , Mary Kate Grabowski 1 1 The Johns Hopkins University, Baltimore, MD, USA, 2 Rakai Health Sciences Program, Kalisizo, Uganda, 3 The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 4 National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA, 5 Leidos Biomedical Research, Inc, Frederick, MD, USA, 6 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA, 7 Centers for Disease Control and Prevention, Kampala, Uganda, 8 The Johns Hopkins University School of Medicine, Baltimore, MD, USA, 9 Makerere University, Kampala, Uganda Background: Self-report of no or inconsistent condom use with non-marital partners is often used as an eligibility criterion for pre-exposure prophylaxis (PrEP), but recent data on HIV incidence by self-reported condom use frequency is limited. Here, we aimed to assess the relationship between HIV incidence and self-reported frequency of condom use among people reporting non-marital sexual partners in Uganda. Methods: We used longitudinal population-based surveillance data from the Rakai Community Cohort Study collected between 2011 and 2018 to evaluate HIV incidence among persons reporting non-marital sexual partners in 40 communities, including four hyperendemic (~40% HIV seroprevalence) Lake Victoria fishing communities. Participants were included irrespective of their marital status. We characterized demographics, risk behaviors, and partnership characteristics by self-reported condom use frequency with non-marital partners. Our primary outcome was incident HIV infection, defined as the first HIV seropositive test result among persons seronegative at their prior visit. HIV incidence rates [IR] per 100 person years (pys) among participants reporting no condom use (never-users), inconsistent condom use (inconsistent-users), and consistent condom use (always-users) were estimated using Poisson regression. Results: Overall, 19,384 participants, including 11,742 men (60.6%), reported 26,621 past-year non-marital partners. Approximately one-third of women

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