CROI 2020 Abstract eBook

Abstract eBook

Poster Abstracts

851 AGE-SPECIFIC HIV INCIDENCE PATTERNS AMONG POPULATION COHORTS IN SUB-SAHARAN AFRICA Kathryn A. Risher 1 , Georges Reniers 1 , Emma Slaymaker 1 , Alain Vandormael 2 , Mark Urassa 3 , Robert Newton 4 , Tom Lutalo 5 , Louisa Moorhouse 6 , Tawanda Dadirai 7 , Amelia C.Crampin 1 , Christophe Fraser 8 , Anne Cori 6 , Milly Marston 1 , Jeffrey Eaton 6 , for the ALPHA Network 1 London School of Hygiene & Tropical Medicine, London, UK, 2 University of KwaZulu-Natal, Durban, South Africa, 3 National Institute for Medical Research, Kisesa HDSS, Mwanza, Tanzania, United Republic of, 4 University of York, York, UK, 5 Rakai Health Sciences Program, Kalisizo, Uganda, 6 Imperial College London, London, UK, 7 Biomedical Research and Training Institute, Harare, Zimbabwe, 8 University of Oxford, Oxford, UK Background: As the HIV epidemic in sub-Saharan Africa matures, it is unclear how patterns of HIV incidence by sex and age have changed. Methods: We used a Bayesian model to jointly reconstruct age-specific HIV incidence and mortality from population-based sero-survey and HIV survival data collected among rural population HIV cohorts in Tanzania (Kisesa), Uganda (Masaka and Rakai), Malawi (Karonga), Zimbabwe (Manicaland) and South Africa (uMkhanyakude). HIV incidence hazard was flexibly modelled using penalised B-splines with knots every 5 years over age and time. The model was fit separately for each sex in each site. Modelled incidence and prevalence results are applied to national standard populations to estimate average age of infection and percentage of new infections at given ages. Results: Age-specific incidence decreased over time across age groups in most studies (Figure). In the earlier years of the epidemic, almost all studies had peak incidence among 20-24 year old women and 25-29 year old men. Over time, age-specific incidence flattened in Masaka, Kisesa, Karonga and Rakai men, while in Manicaland the age-specific incidence peaks at a later age and uMkhanyakude and Rakai women maintained the same peaks. Average age at infection is higher in men than women across all studies. While relatively stable across time, average age at infection increases from 2000 to 2017 (or max year of data collection) in Kisesa (+1.8 years among men and +2.7 among women), Masaka (+1.3 men, +1.2 women), Manicaland (+2.3 men, +1.7 women), and Karonga women (+0.2), though there were decreases in Karonga men (-0.2), Rakai (-0.1 men, -0.3 women) and uMkhanyakude (-2.0 men, -2.4 women). The percentage of women’s infections occurring among 15-24 year olds, the age range targeted in major HIV prevention, is above 50% in the most recent year for 3 of 6 studies: Rakai (64%, 95% CI=44-76%), uMkhanyakude (58%, 95% CI=54-62%), and Masaka (51%, 95% CI=35-64%). In the other three sites, this proportion was: Kisesa (38%, 95% CI=26-53%), Karonga (35%, 95% CI=25- 44%), and Manicaland (41%, 95% CI=33-49%). Conclusion: Our evidence suggests that age-specific incidence is declining over time in these six study sites, though the magnitude and timing of this decline varied by site. Among adult women, between 35-65% of new infections occurred among adolescent girls and young women aged 15-24.

852 HIGH HIV INCIDENCE AND VOLUNTEER RETENTION IN A BANGKOK- BASED COHORT OF MSM AND TGW Tanyaporn Wansom 1 , Sant Muangnoicharoen 2 , Sorachai Nitayaphan 3 , Suchai Kitsiripornchai 3 , Trevor A. Crowell 1 , Leilani Francisco 1 , Qun Li 1 , Peter Dawson 4 , Merlin L. Robb 1 , Kirsten Smith 5 , Elizabeth A. Heger 5 , Punnee Pitisutthithum 2 , Robert J. O'Connell 3 , Sandhya Vasan 1 , for the RV348 Study Group 1 Henry M Jackson Foundation, Bethesda, MD, USA, 2 Mahidol University, Bangkok, Thailand, 3 Armed Forces Research Institute of Medical Sciences in Bangkok, Bangkok, Thailand, 4 Emmes Corporation, Rockville, MD, USA, 5 United States Army Medical Materiel Agency, Frederick, MD, USA Background: Men who have sex with men (MSM) and transgender women (TGW) bear a disproportionate burden of new HIV infections. We characterized HIV incidence and retention in MSM and TGW in Bangkok, Thailand, to evaluate suitability and preparedness for potential future efficacy trials of preventive HIV vaccines. Methods: From April to October 2017, HIV-uninfected Thai MSM and TGW aged 18-35 years were recruited into an 18-month prospective cohort at two sites independently: Royal Thai Army (RTA) and Vaccine Trial Centre at Mahidol University (VTC). Participants had been assigned male sex at birth and reported anal intercourse in the preceding six months with at least one of the following: condomless anal intercourse with a man or TGW living with HIV or of unknown HIV status; ≥3 sexual partners; exchange of sex for money or goods; or diagnosis of any sexually transmitted infection. Participants answered comprehensive behavioral questionnaires and were screened for HIV using sequential rapid tests. We used Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) associated with HIV acquisition. Results: Of 1184 screened, 87 (7.1%) were excluded due to prevalent HIV infection, and 1017 were prospectively enrolled with median age 22 years (interquartile range 20-25), including 349 (34.3%) TGW. At enrollment, syphilis was diagnosed in 39 (3.8%), hepatitis B in 15 (1.5%), and hepatitis C in 2 (0.2%). 805 (79%) participants expressed willingness to participate in a HIV vaccine trial, 532 (55.2%) reported having heard of pre-exposure prophylaxis (PrEP), and none reported current PrEP use. A total of 942 (92.6%) participants were retained through the end of the study. During 1422 person-years (PY) of observation, 53 incident HIV infections were diagnosed (3.73 [95% CI 2.79-4.87] cases/100PY). Among 256 candidate models evaluated, the one with the lowest Akaike’s information criterion contained age, site, and prior HIV testing (Fig.1). Increased age was associated with lower hazard of incident HIV (HR 0.84 [95%CI 0.76-0.93]) and prior HIV testing was associated with increased hazard of incident HIV (2.16 [95%CI 1.23-3.79]. Conclusion: Thai MSM and TGW in this study demonstrated high HIV incidence and are in need of effective HIV prevention interventions. Good retention in this cohort demonstrates the feasibility of future efficacy testing of such interventions.

Poster Abstracts

853 HIV AMONG FEMALE SEX WORKERS: RISK FACTORS AND LESSONS FROM A NATIONAL SURVEY Adedayo O. Adeyemi 1 , Emmanuel Abatta 2 , Olubunmi Fakunle 1 , Ogbonna O. Amanze 3 1 University of Abuja Teaching Hospital, Abuja, Nigeria, 2 Ministry of Health, Abuja, Nigeria, 3 National Agency for the Control of AIDS, Abuja, Nigeria

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