CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

1025 Ultra-High Resolution GPS to Measure Human Mobility in High HIV Prevalence Areas in Rural S Africa Khai Hoan Tram 1 , Elphas Okango 2 , Thulile Mathenjwa 2 , Paul Mee 3 , Hae-Young Kim 4 , Till Bärnighausen 5 , Adrian Dobra 1 , Frank Tanser 6 1 University of Washington, Seattle, WA, USA, 2 Africa Health Research Institute, Mtubatuba, South Africa, 3 Lincoln International Institute of Rural Health, Lincoln, United Kingdom, 4 New York University Grossman School of Medicine, New York, NY, USA, 5 Heidelberg University, Heidelberg, Germany, 6 Stellenbosch University, Cape Town, South Africa Background: Mobility, including both short-term travel and migration, has been linked to increased risk of HIV infection. Ultra-high resolution GPS data collected from study participants who carry smartphones during their daily activities offers new insights into the mobility patterns of a representative sample of young adults in an HIV hyper-endemic setting in rural KwaZulu-Natal, South Africa. Methods: This study involved a random sample of adults aged 20-30 years who were consented and tested for HIV in the 2019 Africa Health Research Institute survey. Between 6/2021 – 3/2023, participants either received a smartphone with a customized Ethica mobile app or installed the app on their own devices. Positional data were recorded at a frequency of up to ~1 second (depending on internet connectivity and movement) over a six-month period. Data was analyzed to explore space-time dimensions of mobility and to quantify time spent in known high HIV prevalence areas. In this analysis, the cluster where each individual recorded the most time spent was considered to be their residential cluster. Results: In total, 27,151,329 time-stamped location records were collected for 202 individuals (median 74,864.5 data points), spatially distributed across 45 clusters within the study area and 57 municipalities across South Africa. Participants recorded a median of 129.7 days (IQR 71.8-161.8) inside the study area versus a median of 17.2 days (IQR 3.0-48.1) outside the study area. Nearly all (97.0%) made at least one trip outside the study area during this time. Similar proportions spent greater than 50% of their recorded time outside their own residential cluster: either in other clusters within the study area [internal mobility: 13.4%] or outside the study area entirely [external mobility: 14.4%]. Over half (88/157, 56.1%) of those participants who did not reside in a geographical HIV cluster spent time in those areas. Median percent of recorded time by non-residents in the HIV clusters was 0.6% (IQR 0.04-5.8). Conclusion: Young adults in rural KwaZulu-Natal display highly dynamic patterns of mobility both locally and farther afield. Over forty percent of this population moved through clusters in the study area with known high HIV prevalence but did not reside in those places. Determining typologies of movement in this age group and quantifying movements in and out of known HIV hotspots can facilitate designing location-intelligent, real-time precision interventions for those at high risk of HIV acquisition.

Background: Female bar workers (FBW) in eastern Africa often engage in sex work. However, population-level data on HIV seroprevalence, incidence, and viral suppression among FBW are rare. Methods: FBW were identified through longitudinal population-based HIV surveillance in southern Uganda via the Rakai Community Cohort Study between 2012 and 2019. Surveillance was conducted across five surveys in four high HIV prevalence (>35%) Lake Victoria fishing communities and 36 moderate HIV prevalence (~12%) inland agrarian and trading communities. Participants were classified as FBW if they reported bar work as a primary or secondary occupation. Sociodemographics and sexual behaviors of FBW were compared with participants never classified as FBW (non-FBW). Primary outcomes included laboratory-confirmed HIV seropositivity, seroincident HIV infection measured via paired serologic testing, and HIV viral load suppression (<200 copies/ml). Prevalence and incidence rate ratios (PR, IRR) were estimated using age-adjusted Poisson regression models with 95% confidence intervals (95%CI). Results: A total of 23,556 female participants contributed 52,708 person-visits. Overall, 1,205 (5.1%) women self-identified as FBW at one or more study visits. FBW were significantly older, more likely to report recent migration, and had substantially higher levels of HIV-associated risk behaviors, including higher numbers of lifetime and prior-year sexual partners and alcohol use before sex, compared to non-FBW. FBW also had significantly higher HIV seroprevalence irrespective of age or community (Figure). Among 364 FBW participating in at least four surveys, only 50 (13.7%) self-reported being a bar worker at all surveys, while 128 (35.2%) reported bar work at only a single survey. Overall, 377 HIV incident events occurred over 41,030 years of participant follow-up. Incidence among FBW was 1.76/100 person-years versus 0.90/100 person-years among non-FBW (adjIRR:2.24; 95%CI: 1.27-3.63). However, FBW living with HIV irrespective of antiretroviral use tended to have higher levels of population HIV viral load suppression compared to non-FBW (62.9% vs 54.9%; adjPR=1.08, 95%CI: 1.01-1.17). Conclusion: Enhanced prevention services for female barworkers in Uganda are needed and may reduce HIV incidence in this population. However, high mobility and frequent fluctuation in and out of bar work may complicate delivery of interventions, such as long-acting injectable pre-exposure prophylaxis.

Poster Abstracts

1027 Large Decline in HIV Prevalence Among Female Sex Workers in Zimbabwe, 2011-2023

James Hargreaves 1 , Sungai Chabata 2 , Sanni Ali 1 , Tsitsi Hove 3 , Harriet Jones 1 , Loveleen Bansi-Matharu 4 , Owen Mugurungi 5 , Raymond Yekeye 6 , Sithembile Musumburi 2 , Jeffrey Dirawo 2 , Primrose Matambanadzo 3 , Fortunate Machingura 3 , Andrew Phillips 4 , Frances M. Cowan 7 1 London School of Hygiene & Tropical Medicine, London, United Kingdom, 2 Centre for Sexual Health & HIV/AIDS Research, Harare, Zimbabwe, 3 Centre for Sexual Health and HIV/AIDS Research Zimbabwe, Harare, Zimbabwe, 4 University College London, London, United Kingdom, 5 Ministry of Health and Child Care, Harare, Zimbabwe, 6 Harare City Health Department, Harare, Zimbabwe, 7 Liverpool School of Tropical Medicine, Liverpool, United Kingdom Background: Little is known about HIV trends among female sex workers (FSW) in Africa. We analysed data from a national-scale collaboration to explore trends in HIV prevalence and HIV incidence among FSW in Zimbabwe between 2011 and 2023, complemented by mathematical modelling. Methods: Between 2011-2023 we collected data on HIV infection from 13,918 women aged 18-39 in multiple respondent driven sampling surveys (RDS) in Zimbabwe, including 13 towns where surveys were repeated in 2017 and 2021, and 2 cities where surveys were repeated in 2017 and, the most recently available data, from 2023. In 2021, we analysed 306 dried blood spot samples with a recent infection algorithm (LAg avidity+Viral load). Using RDS-II

1026 HIV Seroprevalence, Incidence, and Viral Suppression Among Ugandan Female Barworkers Xinyi Feng 1 , Slisha Shrestha 2 , Fred Nalugoda 3 , Godfrey Kigozi 3 , Robert Ssekubugu 3 , Larry W. Chang 1 , Andrea Wirtz 2 , Caitlin E. Kennedy 2 , Arthur G. Fitzmaurice 4 , Gertrude Nakigozi 3 , Aaron A. R. Tobian 1 , Steven J. Reynolds 5 , Joseph Kagaayi 3 , Mary Kate Grabowski 1 1 The Johns Hopkins University School of Medicine, Baltimore, MD, USA, 2 The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 3 Rakai Health Sciences Program, Kalisizo, Uganda, 4 Centers for Disease Control and Prevention, Kampala, Uganda, 5 National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA

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