(P233) Neisseria gonorrhoeae and Chlamydia trachomatis positivity by symptom status and anatomic site of infection among men who have sex with men in a HIV Pre-exposure Prophylaxis program in Hanoi, Vietnam

Background: Routine screening for sexually transmitted infections (STIs) is recommended for patients using human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) due to high rates of asymptomatic bacterial STIs. However, in Vietnam, as in many other low-resource settings, management of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections is primarily syndromic due to limited resources for testing. The study objectives were to evaluate CT and/or NG test positivity at three anatomic sites among symptomatic and asymptomatic participants in an HIV PrEP program in Vietnam.

Methods: From January-December 2022, participants in the HIV PrEP program at the Sexual Health Promotion Clinic in Hanoi, Vietnam were enrolled. Study participants completed a survey collecting demographic, behavioral and clinical characteristics. Participants self-collected urine, rectal, and pharyngeal specimens for nucleic-acid amplification testing. Participants positive for CT and/or NG were recalled for treatment.

Results: In total, 529 participants were enrolled. All were male and reported having sex with men in the prior 12 months; the median age was 25.1 years (IQR: 21.7– 29.65). The overall prevalence of CT or NG infection was 29.3% (155/529). The prevalence was 20.5% (108/529) for CT and 14.6% (77/529) for NG. By anatomic site, there were 34 (6.4%) urethral, 95 (18.0%) rectal, and 83 (15.7%) pharyngeal CT or NG infections. Among the 155 participants with CT or NG infections at any site, more than half (56.1%; 87/155) had no urethral, rectal or pharyngeal symptoms in the prior week. CT or NG test positivity among those reporting symptoms was 9.8% for urethral, 18.6% for rectal and 19.5% for pharyngeal. Positivity rate for CT or NG among asymptomatic participants was 4.1%, 17.5% and 13.1% for urethral, rectal, and pharyngeal respectively.

Conclusion: Through routine screening at three anatomic sites, we observed a high prevalence of CT and NG infections among MSM in a PrEP program in Hanoi, Vietnam. While more than half of the infections occurred among those asymptomatic, test positivity was higher among those with symptoms.