Absence of Lymphogranuloma Venereum Among Men Who Have Sex With Men With Rectal Chlamydia trachomatis Infections Within an HIV Preexposure Prophylaxis Program in Hanoi, Vietnam
Bibliographic record
Abstract
Dear Editor, We read with great interest the study by Gupta et al.1 on the increasing number of lymphogranuloma venereum (LGV) cases in British Columbia, Canada. The LGV infections were primarily among men who have sex with men (MSM) on HIV preexposure prophylaxis (PrEP) and were more likely to be asymptomatic. Although considered to be rare in high-income countries, LGV cases disproportionately affect MSM and are being observed with increasing frequency among HIV-uninfected men on HIV PrEP.2–5 Lymphogranuloma venereum is considered endemic to parts of Southeast Asia, yet epidemiologic data from the region are sparse. One recent report among MSM in Taiwan found that the prevalence of LGV rectal infections was 1.6%.6 In Vietnam, we have found a high prevalence of rectal Chlamydia trachomatis infections among MSM, but the prevalence of LGV is not known.7 Given increasing reports of LGV in other settings, we sought to understand the prevalence of LGV among MSM in an HIV PrEP program in Hanoi, Vietnam. From January 2022 to May 2023, HIV PrEP program participants in Hanoi who were male and reported having sex with men or transgender women in the prior 12 months were enrolled in a study on the prevalence of C. trachomatis and Neisseria gonorrhoeae infections. Participants self-collected rectal, pharyngeal, and urine samples for testing by nucleic acid amplification testing using either the Roche cobas CT/NG or Abbott m Alinity STI assays. Remnant specimens were stored at −80°C, and a subset was selected from available rectal specimens with C. trachomatis to undergo LGV testing. DNA extraction was performed using QiaAmp Mini Kit (Qiagen, Hilden, Germany), with internal controls. The non-LGV/LGV real-time polymerase chain reaction assay was conducted using a 168-bp fragment of the pmpH gene for amplification, as described previously.8 The prevalence of rectal C. trachomatis infections in the parent study was 14%. In total, 90 rectal specimens with C. trachomatis infections were selected for LGV testing, with 31% being from participants reporting rectal symptoms in the prior week. All the specimens were negative for LGV by real-time polymerase chain reaction. Internal controls were positive for DNA extraction for all specimens; 8 specimens (8.9%) were negative for both LGV and non-LGV, suggesting a low amount of C. trachomatis DNA. Screening for LGV in rectal C. trachomatis infections among 90 MSM in an HIV PrEP program in Hanoi, Vietnam, did not identify any LGV infections. Despite the increasing prevalence of LGV infections among MSM in some settings, there does not appear to be a substantial prevalence in our setting. Recent reports from China and Thailand also did not show LGV infections in MSM populations.9,10 The absence of LGV infections in our study might be the result of the relatively limited number of samples tested or reflect the study setting, which was one HIV PrEP program in Hanoi, and might not represent other LGV infections in other settings. Additional research is needed to more comprehensively understand the epidemiology of the LGV infections in the region, particularly among populations living with HIV and on HIV PrEP. Tien V. Quang, MS Phacogen Institute of Technology Hanoi, VietnamHao T.M. Bui, PhD, MPHLoc Q. Pham, MD, PhDGiang M. Le, MD, PhD Center for Training and Research on Substance Abuse—HIV Hanoi Medical University Hanoi, VietnamHoi T. Le, MD, PhD Phacogen Institute of Technology Hanoi, VietnamJeffrey D. Klausner, MD, MPH Department of Population and Public Health Sciences Keck School of Medicine University of Southern California Los Angeles Los Angeles, CAPaul C. Adamson, MD, MPH Division of Infectious Diseases David Geffen School of Medicine University of California Los Angeles Los Angeles, CA [email protected]
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".