CROI 2025 Abstract eBook

Abstract eBook

Poster Abstracts

1244 Syphilis Among Women of Reproductive Age With or Without HIV in the Southern US Maria L. Alcaide 1 , Erin R. Carr 1 , Candice A. Sternberg 1 , Nicholas F. Fonseca Nogueira 2 , Laura Beauchamps 1 , Patricia Racchamarich 2 , Jonell E. Potter 1 , Daniel Westreich 3 , Seble Kassaye 4 , Elizabeth F. Topper 5 , Aadia Rana 6 , Deborah Konkle Parker 7 , Deborah L. Jones 2 , Anandi N. Sheth 8 , Madison S. Meyer 2 1 University of Miami Miller, Miami, FL, USA, 2 University of Miami, Miami, FL, USA, 3 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA, 4 Georgetown University, Washington, DC, USA, 5 The Johns Hopkins University, Baltimore, MD, USA, 6 University of Alabama at Birmingham, Birmingham, AL, USA, 7 University of Mississippi Medical Center, Jackson, MS, USA, 8 Emory University, Atlanta, GA, USA Background: Syphilis is associated with increased risk of HIV acquisition and poor pregnancy outcomes, including congenital syphilis. Syphilis remains a threat to public health despite accessible screening and treatment. This study examines the prevalence of syphilis among reproductive-age (18-45 years) women with or without HIV enrolled between 2021 and 2023 in the Study of Treatment and Reproductive Outcomes (STAR), an observational cohort across six Southern U.S cities. Methods: Demographic, medical (prior diagnosis of syphilis, presence of a rash or genital ulcerations) and obstetric data are collected as well as syphilis screening using a nontreponemal test (RPR) with treponemal test for confirmation, or the reverse sequence algorithm. Women with two different reactive tests (two treponemal or one treponemal plus one non treponemal) were categorized based on self-reported history of syphilis and RPR titer as possible: (1) recent infection (no history of syphilis, and RPR ≥1:8), (2) recent reinfection/reactivation (history of syphilis with RPR ≥1:8), (3) late latent syphilis (no history of syphilis and RPR <1:8), or (4) serofast status (history of syphilis with RPR <1:8). Cross-sectional data was examined and associations between pregnancy, HIV status, and syphilis were evaluated. Results: A total of 785 women underwent syphilis testing. Median age was 35 years (IQR 29-40); 580 (74.2%) were non-Hispanic Black, 87 (11.1%) Hispanic, and 80 (10.2%) non-Hispanic White. Observed syphilis cases were 9 (1.5%): 2 (0.3%) recent infection, 2 (0.3%) reinfection/reactivation, and 5 (0.6%) late latent. Among 88 pregnant women, there were 2 (2.3%) syphilis cases with reinfection/reactivation. Among 461 women with HIV there were 6 syphilis cases: 2 (0.4%) had reinfection/reactivation and 4 (0.9%) late latent syphilis. There were no differences in syphilis prevalence by pregnancy (p=0.263) or HIV status (p=0.742). Overall, 14 (1.8%) women had serofast status, of those 2 were pregnant and 6 living with HIV. Conclusions: The well-established link between syphilis and HIV underscores the importance of equitable, integrated screening and treatment programs for high-risk women of reproductive age in the Southern U.S. Despite no associations with HIV status or pregnancy, this study highlights the continuous high prevalence of syphilis, emphasizing an urgent need to address these interconnected public health challenges among reproductive age women. 1245 Epidemic of Treponema pallidum Strains in Japan and Biomarkers for Molecular Epidemiology Eisuke Adachi, Wakana Sato, Ayako Sedohara, Hiroshi Yotsuyanagi, Yasutoshi Kido University of Tokyo Institute of Medical Science, Tokyo, Japan Background: The difficulty in culturing Treponema pallidum ( T. pallidum ) has limited molecular-biological analyses. This study aims to establish a molecular epidemiological analysis using the multi-locus sequence typing (MLST) scheme with whole blood specimens and to explore the relationship between T. pallidum bacteremia and its associated pathophysiology. Methods: We used whole blood specimens from participants serologically diagnosed with syphilis in Tokyo, Japan, between February 2019 and June 2022, about 97% of whom were men who have sex with men (MSM). Sequences for three loci (TP0136, TP0548, and TP0705) required for MLST were obtained, and we analyzed the relationship between PCR positivity and associated markers (e.g., C-reactive protein (CRP), rapid plasma regain (RPR), T. pallidum latex agglutination (TPLA)) Results: Of the 71 whole blood samples, 26 (36.6%) were PCR-positive for TP0136, and sequences for the three loci required for MLST were obtained from 22 samples (31.0%). The most frequently detected sequence type (ST) was ST3 (n=9), followed by ST6 (n=6). Phylogenetic analysis showed that 12 samples belonged to the SS14-like genetic group (12/20, 60%), while 8 samples were classified within the Nichols-like group (8/20, 40%). A new allele was identified in TP0136 . Notably, Treponema pallidum subsp. endemicum, the causative agent

of bejel, was detected in three samples (12%, 3/26). The Cochran-Armitage test for trend also failed to reveal an increase in TP0136 detection as TPLA levels increased (p = 0.056, Table 3). Similarly, the TP0136 detection rate did not exhibit a significant association with the RPR cut-offs of 10 RU (p = 0.40) or 100 RU (p = 0.21). The trend test did not show an increase in TP0136 detected as the RPR increased (p = 0.12). In contrast, positive CRP levels were significantly associated with TP0136 detection at cut-offs of 0.1 mg/dL (p = 0.0007) or 0.5 mg/dL (p < 0.0001). For CRP ≥ 0.5 mg/dL, 77.0% were positive for TP0136 . A trend test further revealed that TP0136 detection significantly increased as CRP levels increased (p < 0.0001) Conclusions: Both SS14-like and Nichols-like strains were circulating concurrently, and Treponema pallidum subsp. endemicum (TEN) may have been sexually transmitted among Japanese MSM. CRP serves as an indicator of test efficiency and could be linked to the presence of pathogens in the bloodstream. 1246 Temporal Changes in Syphilis Prevalence and Population Characteristics Among MSM in India Mihili Gunaratne 1 , Allison M. McFall 1 , Matthew Hamill 2 , Talia A. Loeb 1 , Griffin J. Bell 1 , Jiban J. Baishya 2 , Ashwini Kedar 3 , Archit Sinha 3 , A. K. Srikrishnan 3 , Sunil S. Solomon 2 , Shruti H. Mehta 1 , Gregory M. Lucas 2 1 The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 2 The Johns Hopkins University School of Medicine, Baltimore, MD, USA, 3 YR Gaitonde Center for AIDS Research and Education, Chennai, India Background: Men who have sex with men (MSM) are at higher risk of syphilis infection compared to heterosexual men. Since 2018, syphilis prevalence has been increasing in high income countries, with limited data from low- and middle-income countries. We previously observed a 3-fold increase in syphilis prevalence between 2012 and 2017 among MSM in India. We aimed to assess further changes in syphilis prevalence and population characteristics between 2017 and 2024. Methods: Respondent driven sampling (RDS) was used to accrue cisgender MSM in Bhopal, Delhi, and Hyderabad, India, for cross-sectional surveys in 2016-2017 and 2023-2024. Participants were tested for syphilis using the rapid plasma reagin (RPR) test and RPR+ samples were tested using treponema pallidum hemagglutination assay (TPHA). Syphilis infection is defined as both RPR+ and TPHA+. We examined trends of syphilis prevalence, demographics, and sexual risk behaviors by survey cycle and city. To assess whether changes in the 2023-2024 population vs 2016-2017 could explain changes in syphilis prevalence, we used propensity scores (generated from correlates of syphilis infection - age, sexual orientation, HIV prevalence, unprotected anal intercourse (UAI), recent sex work, and number of male/transgender partners) to indirectly standardize the 2023- 2024 population and re-estimate syphilis prevalence. Analyses incorporated RDS-II weights. Results: 3001 MSM and 2249 MSM from the 2016-2017 and 2023-2024 surveys, respectively, were included. Median age was 27 and 28 in the 2016-2017 and 2023-2024 surveys, respectively. Having a high school education or above increased from 45% to 72%. Syphilis prevalence increased nearly 2.5-fold from 7% to 16%, with increases across all sites (Figure). HIV prevalence increased from 15% to 20%, but prevalence of detectable HIV viremia decreased from 37% to 25%, recent UAI increased from 39% to 47%, and recent history of sex work decreased from 12% to 7%. The indirect standardized syphilis prevalence in the 2023-2024 cycle using propensity scores was 14%. Conclusions: In these 3 Indian cities, we observed substantial recent increases in syphilis prevalence among MSM. Syphilis prevalence remained high after accounting for changes in population characteristics, including risk behaviors such as UAI. Regardless, these data highlight the urgent need for interventions (e.g., DoxyPEP) to address the rising burden of syphilis and potentially other STIs in low- and middle-income countries.

Poster Abstracts

CROI 2025 411