CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

1015 HIV-1 Outbreak Among PWID in Thessaloniki: Recent Expansion in the Midst of COVID-19 Pandemic Evangelia G Kostaki 1 , F. Chatzopoulou 2 , S. Roussos 1 , E. Tsirogianni 2 , M. Psichogiou 1 , I. Goulis 2 , L. Skoura 2 , S. Metallidis 2 , C. Tsiara 3 , G. Magiorkinis 1 , A. Beloukas 4 , A. Hatzakis 1 , V. Sypsa 1 , D. Chatzidimitriou 2 , D. Paraskevis 1 1 University of Athens, Athens, Greece, 2 Aristotle University of Thessaloniki, Thessaloniki, Greece, 3 Hellenic National Public Health Organization, Marousi, Greece, 4 University of West Attica, Athens, Greece Background: During the implementation of "ALEXANDROS", a community based programme, an HIV-1 outbreak was identified among people who inject drugs (PWID) in Thessaloniki, the second largest city in Greece, between 2019 and 2021. Preliminary phylogenetic analysis suggested that 25 sequences from PWID sampled in Thessaloniki during 2019-2021, belonged to 3 phylogenetic clusters of subsubtype A6 and 1 cluster of subsubtype A1. We aimed to investigate the characteristics of this new outbreak by means of molecular epidemiology. Methods: Phylodynamic analysis was performed for subsubtype A6 including 3 phylogenetic clusters consisting of 3 (2 PWID and 1 non-PWID sequences), 12 (10 PWID and 2 non-PWID sequences), and 19 (11 PWID and 8 non-PWID sequences) sequences from Thessaloniki. Additionally, we included in our analysis 5 PWID sequences obtained between 2010 and 2015 as well as several non-PWID sequences since these 3 phylogenetic clusters were part of a larger monophyletic cluster from Thessaloniki. Phylodynamic analysis was performed by using the Bayesian approach and birth-death skyline serial model in BEAST v2.7.4 program. Results: Molecular clock analysis showed that the most recent common ancestor (tMRCA) of the largest (N=11) and the second largest (N=10) cluster from PWID, was estimated in the middle of October 2018 and in May 2014, respectively. For the third PWID cluster (N=2), the tMRCA was estimated in July 2017. Phylodynamic analysis showed that the effective reproductive number (Re) started to increase at the beginning of 2019 and remained high (Re > 1) until the end of the study period in the end of 2021. Moreover, the spatial origin of all the clusters was from Thessaloniki. Conclusion: Our study provides a detailed figure about an HIV-1 outbreak in Thessaloniki. Phylodynamic analysis showed that the time of epidemic growth coincided with the time of the initial identification in 2019. Our findings showed that HIV-1 transmission continues at high rates (Re > 1) among PWID until the end of 2021. Notably, the covid-19 pandemic did not avert HIV-1 transmission among this group. The early origin of the three clusters suggests that HIV-1 virus spreading among this group was previously circulated in the same area. The continuous spread of HIV-1 among this highly vulnerable group is alarming and requires implementation of public health measures. 1016 Disparities in HIV Care Among Hispanic/Latino Persons by Birthplace and SVI: United States, 2021 Juliet A Morales , Zanetta Gant Sumner, Xiaohong Hu, Shacara Johnson Lyons, Anna Satcher Johnson Centers for Disease Control and Prevention, Atlanta, GA, USA Background: Hispanic/Latino persons (Latino hereafter) comprise 19% of the U.S. population but accounted for 29% of new HIV infections in 2021. Latino persons have historically been treated as a homogenous group in public health research despite their social and cultural diversity. This study aimed to assess birthplace and Social Vulnerability Index (SVI) differences among Latino persons not linked to HIV care and without viral suppression in the U.S. Methods: Data from CDC's National HIV Surveillance System were used for Latino persons aged ≥18 years with HIV diagnosed during 2021. Data were limited to 48 U.S. jurisdictions with complete reporting of laboratory results to CDC. Cases were linked via census tracts to CDC/ATSDR's SVI. Non-linkage to care was defined as no documentation of ≥1 CD4 or VL tests within 1 month of HIV diagnosis. Non-viral suppression was defined as no VL test result of <200 copies/mL within 6 months of HIV diagnosis. Adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs) were estimated using Poisson regression model. Results: Among 5,056 Latino persons with HIV diagnosed in 2021, approximately half (51.5%) were born in the U.S., 17.3% in Mexico, 9.2% in Central America, 11.1% in South America, and the remaining 10.9% in the Caribbean (including Puerto Rico and Cuba). Compared with persons born in the U.S. (U.S. states and DC), persons born in Mexico (non-linkage aPR 0.72, 95% CI 0.58–0.90) and South America (aPR 0.78, 95% CI 0.61–1.00) had a

viremia using other point pattern and spatial autoregressive techniques can further assess spatial associations with ARTCs. Identifying distinct geographic areas characterized by high viremia can provide targets for field-based mobile strategies incorporating testing, prevention and treatment to interrupt transmission.

1014 HIV-1 Transmission Dynamics Among People Who Inject Drugs on the US/ Mexico Border Amid COVID-19 Britt Skaathun 1 , Steffanie Strathdee 1 , Cho-Hee Shrader 2 , Carrie Nacht 1 , Annick Borquez 1 , Irina Artamonova 1 , Alicia Harvey-Vera 3 , Carlos Vera 1 , Gudelia Rangel 4 , Caroline Ignacio 1 , Brendon Woodworth 1 , Antoine Chaillon 1 , Tetyana Vasylyeva 1 1 University of California San Diego, La Jolla, CA, USA, 2 Columbia University, New York, NY, USA, 3 University of California San Diego, San Diego, CA, USA, 4 United States-México Border Health Commission, Tijuana, Mexico Background: We assessed HIV prevalence, incidence, and patterns of phylogenetic clustering and cluster growth in networks among people who inject drugs (PWID) in the U.S./Mexico border region during the COVID-19 pandemic. Methods: We conducted secondary analysis of a longitudinal study of PWID aged ≥18 years from 3 groups: PWID who live in San Diego county (SD) and engaged in cross-border drug use in Tijuana ≤24 months ago (SD CBDUs), and PWID who did not engage in cross-border drug use (NCBDUs), and who live in either SD or Tijuana (TJ). Between Oct/2020-Oct/2021, participants underwent semi-annual surveys and provided samples for HIV. We calculated HIV prevalence and bivariate incidence-density rates (IR) between baseline and 18-month follow-up visits. Bayesian phylogenetic analysis was used to identify local transmission clusters and estimate their age (as time to most recent common ancestor, TMRCA). We further applied a birth-death skyline model to estimate changes in the effective reproductive number of large local transmission clusters (Re). Results: At baseline (n=612), HIV prevalence was 8% (4% SD CBDU, 4% SD NCBDU, 16% TJ NCBDU). Of HIV-seronegative PWID at 18 months follow-up, 9 HIV seroconversions occurred (IR: 1.357 per 100 person-years (95% CI: 0.470, 2.243) 7 of whom were TJ NCBDU and 2 were SD CBDU. We identified 16 phylogenetic clusters that included at least 1 sequence from the cohort (cluster size range 2-17), among which 9 (56%) had sequences from both the U.S. and Mexico. Three dyads had highest posterior density (HPD) intervals of TMRCA estimated to overlap with the COVID-related US-Mexico border closure in 2020 and all included participants from both sides of the border. One of the two identified large clusters (N=15) included TJ NCBDU and SD CBDU participants only, 47% of the cluster reported sex work, and continued to grow during the border closure (Re=4.8, 95% HPD 1.5 – 9.1]. Conclusions: During the COVID-19 pandemic, HIV phylogenetic clusters were detected with sequences from both sides of the border, one of which continued to grow despite the border closure. Despite relatively low HIV incidence overall, mobile harm reduction services providing syringes and HIV testing, and coordination with municipal HIV programs to initiate ART and PrEP are needed to reduce transmission, particularly in Tijuana.

Poster Abstracts

CROI 2024 325