Abstract
OBJECTIVES: To assess the prevalence, anatomical distribution, and correlates of Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) infections within an HIV pre-exposure prophylaxis (PrEP) program in Hanoi, Vietnam. DESIGN: Cross-sectional, observational study. METHODS: Between January-December 2022, HIV PrEP program clients who were male at birth, ≥16 years old, reported ≥1 male sex partner in the prior 12 months, were enrolled. A questionnaire collected sociodemographics, sexual behaviors, and clinical data. CT/NG testing was performed on self-collected urine, rectal, and pharyngeal specimens. Multivariate logistic regression was used to identify factors associated with infections. RESULTS: Among 529 participants, the prevalence of CT or NG was 28.9% (153/529). The prevalence of NG was 14.4% (76/529) and highest for pharyngeal infections (11.7%; 62/528), while for CT, the prevalence was 20.4% (108/529) and highest for rectal infections (15.0%; 74/493). Symptoms in the prior week were reported by 45.8% (70/153) of those with CT or NG infections. Among asymptomatic participants, there was a low prevalence of urethral CT (3.1%; 14/457) and NG (0.9%; 4/457). Condomless anal sex (aOR= 1.98; 95% CI: 1.27, 3.09) and sexualized drug use in the prior 6 months (aOR= 1.71; 95% CI: 1.09, 2.69) were associated with CT/NG infections. CONCLUSIONS: The study found a high prevalence of CT/NG infections, particularly pharyngeal and rectal infections, within an HIV PrEP program in Hanoi, Vietnam. The findings suggest testing for urethral infections among asymptomatic individuals is of limited value. Further research is needed for STI prevention strategies and updated guidelines for CT/NG screening in HIV PrEP programs in low- and middle-income countries.