CROI 2024 Abstract eBook

Abstract eBook

Poster Abstracts

1068 Increasing Intra- and Inter-Subtype HIV Diversity Despite Rapidly Declining HIV Incidence in Uganda Seungwon Kim 1 , Michael A. Martin 1 , Ronald M. Galiwango 2 , Oliver Laeyendecker 3 , Thomas C. Quinn 3 , Godfrey Kigozi 2 , Robert Ssekubugu 2 , David Bonsall 4 , Steven J. Reynolds 2 , Brian Foley 5 , Lucie Abeler-Dörner 4 , Christophe Fraser 4 , Oliver Ratmann 6 , Joseph Kagaayi 2 , Mary Kate Grabowski 7 1 The Johns Hopkins University School of Medicine, Baltimore, MD, USA, 2 Rakai Health Sciences Program, Kalisizo, Uganda, 3 National Institute of Allergy and Infectious Diseases, Baltimore, MD, USA, 4 University of Oxford, Oxford, United Kingdom, 5 Los Alamos National Laboratory, Los Alamos, NM, USA, 6 Imperial College London, London, United Kingdom, 7 The Johns Hopkins University, Baltimore, MD, USA Background: HIV incidence has been declining in sub-Saharan Africa with scale-up of HIV interventions. However, there is limited data on HIV evolutionary trends in African populations with declining epidemics. Here, we evaluated changes in HIV diversity over a twenty-five-year period spanning the introduction and scale-up of HIV prevention and treatment programs in Uganda. Methods: We used HIV sequence and survey data from the Rakai Community Cohort Study, a longitudinal population HIV surveillance cohort in southern Uganda. p24 and gp41 consensus sequence data were generated from blood samples of persons living with HIV (PLHIV) in 31 inland semi-urban trading and agrarian communities (1994 to 2018) and four hyperendemic Lake Victoria fishing communities (2011 to 2018) under continuous surveillance. HIV subtype was assigned using the Recombination Identification Program with phylogenetic confirmation. Inter-subtype diversity was estimated using the Shannon diversity index and intra-subtype diversity with the nucleotide diversity and pairwise TN93 genetic distances. Evolutionary dynamics were assessed among demographic and behavioral sub-groups and by migration status. Results: HIV genomic data were available from 4,999 PLHIV, including 3,060 and 1,939 persons residing in inland and fishing communities, respectively, and from 1,484 HIV seroincident cases. In inland communities, subtype A1 viruses proportionately increased in p24 from 17% in 1995 to 32% in 2018 (p<0.001) and in gp41 from 21% in 1995 to 48% in 2018 (p<0.001), while those of subtype D declined in p24 from 80% in 1995 to 45% in 2018 (p<0.001) and in gp41 from 76% in 1995 to 38% in 2018 (p<0.001). In both genes, an increasing proportion of viruses were classified as recombinants (e.g., in p24 from 2.7% in 1994 to 21.4% in 2018 in inland communities). While p24 intra-subtype genetic diversity leveled off after 2014, diversity of gp41 increased through 2018. Inter- and intra-subtype viral diversity generally increased across all population sub-groups, including among individuals with no recent migration history or extra-community sexual partners. Conclusion: Although HIV incidence has declined in Uganda, intra and inter-subtype HIV diversity has increased. Continued molecular surveillance may provide a better understanding of the dynamics driving population HIV evolution and yield important insights for epidemic control.

1069 HIV-1 A6 Variant Transmissions Poland Are Fuelled by War Refugees From Ukraine & Local MSM Clusters Karol Serwin 1 , Kaja Scheibe 1 , Anna Urbańska 1 , Bogusz Aksak-Wąs 1 , Magdalena Witak-Jędra 1 , Piotr Ząbek 2 , Ewa Siwak 2 , Iwona Cielniak 3 , Paweł Jakubowski 4 , Monika Bociąga-Jasik 5 , Elźbieta Mularska 6 , Bartosz Szetela 7 , Aleksandra Szymczak 7 , Milosz Parczewski 1 1 Pomeranian Medical University, Szczecin, Poland, 2 Medical University of Warsaw, Warsaw, Poland, 3 Cardinal Stefan Wyszyński University in Warsaw, Warsaw, Poland, 4 Pomeranian Hospitals, Gdańsk, Poland, 5 Jagiellonian University, Kraków, Poland, 6 Medical University of Łódź, Łódź, Poland, 7 Wrocław Medical University, Wrocław, Poland Background: Since February 2022, Poland has become a shelter for over 1.6 million Ukrainian refugees, a number comparable to the total migrant flow of the past decade. The HIV-1 A6 lineage, dominant in Eastern Europe, has become the most common variant in Poland in the recent years, previously dominated by subtype B infections. Phylogenetic analysis yields insights into transmission clusters and linkages, offering a deeper understanding of ongoing virus spread. In this study we explore the changing epidemic profile of the A6 lineage in Poland in the context of migration and refuge but also local transmissions. Methods: We analyzed 1941 Polish HIV partial pol sequences, including 719 from Ukrainian-born individuals, supplemented with 11,807 location-annotated A6 sequences, collected up until November 2023. Phylogenetic inference and genetic distance-based clustering were employed to identify clusters and genetically linked individuals. Clusters were classified into singletons and dyads (≤2 sequences), networks (3–13 sequences), or large clusters (≥14 sequences). Further, in the Polish cohort, we delineated sequences from individuals born in Poland or Ukraine and analysed transmission routes within clusters. Results: We identified six large clusters (n=855 sequences), 74 networks (n=353), and 590 singletons or dyads (n=733). In large clusters dominated internal Polish transmissions among men who have sex with men (MSM) accounting for the total of 41.9% of infections with known transmission route. There was also a marked rise in new, late diagnosed (lymphocyte count at baseline < 350 cells/μl) cases was observed among Ukrainian male (13.6%) and female (13.3%) migrants since the beginning of 2022, representing new introductions of the A6 lineage into Poland, primarily as singletons and dyads but without further spread into larger clusters. The most common international linkages were observed from Ukrainian migrants diagnosed before 2022 to individuals born in Poland (35.0% of the normalized links). Conclusion: The influx of war-displaced people from Ukraine notably fuels sub-subtype A6 infections in Poland but majority of introductions resulted in dead-end transmissions. On the other hand, large clusters define independently growing national epidemic with this variant in MSM. Presented data imply urgent need for targeted HIV testing and intervention programs among key populations. The figure, table, or graphic for this abstract has been removed. Antoine Chaillon 1 , Alan Wells 1 , Sanjay R Mehta 2 , Susan J. Little 1 1 University of California San Diego, La Jolla, CA, USA, 2 VA San Diego Healthcare System, La Jolla, CA, USA Background: The Miami-Dade HIV epidemic is one of the largest and most active regional epidemics in the US. While predominantly an epidemic among men who have sex with men (MSM), there is significant diversity across ethnicity, race, risk group and geography. We characterized the dynamics of HIV transmission between neighborhoods and risk groups in the Miami-Dade region to inform the development of focused interventions. Methods: A comprehensive public health dataset of 7274 HIV-1 subtype B partial pol sequences sampled from unique persons with HIV (PWH) between 2015-2020 was combined with a closely related background dataset of 4,250 publicly available sequences. A multistep phylogenetic approach was applied: (1) maximum likelihood phylogenetic inference to identify well-supported monophyletic clades of size ≥5 including ≥2 distinct Miami-Dade neighborhood groups (NBHD), as defined by Florida Department of Health; (2) local clades were used to perform a discrete phylogeographic inference to evaluate transmission dynamics between NBHD (but not within a NBHD) after 2010. Additional metadata including stage of infection was also incorporated into the analysis to estimate migration between NBHDs to evaluate migration between risk groups. Results: We identified 3,737 HIV sequences forming 315 transmission clusters of ≥5 sequences (range 5–130) that included PWH from at least two NBHDs. PWH belonging to these clades were predominantly male (76%), Hispanic 1070 HIV Spread in Miami-Dade County

Poster Abstracts

CROI 2024 345