Prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae infection among Men who have sex with men in a human immunodeficiency virus pre-exposure prophylaxis program in Hanoi, Vietnam

Abstract

The study objectives were to determine Chlamydia trachomatis (Ct) and/or Neisseria gonorrhoeae (Ng) test positivity at three anatomic sites among symptomatic and asymptomatic male participants in an HIV PrEP clinic. Participants in the HIV PrEP program at the SHP Clinic in Hanoi, Vietnam were enrolled in 2022. Participants self-collected urine, rectal, and pharyngeal specimens for nucleic-acid amplification testing. Study participants self-administered an online survey collecting demographic, behavioral and clinical characteristics. In total, 529 participants were enrolled. All were male and reported having sex with men (MSM) in the prior 12 months; the median age was 25.1 years (IQR: 21.7– 29.7). The overall prevalence of Ct or Ng infection was 29.3%. The prevalence was 20.5% for Ct and 14.6% 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%) had no urethral, rectal or pharyngeal symptoms in the prior week. Ct or Ng test positivity among those reporting symptoms was 4.0% for urethral, 7.6% for rectal and 12.9% for pharyngeal. Positivity rate for Ct or Ng among asymptomatic participants was 2.5%, 10.4% and 7.8% for urethral, rectal, and pharyngeal respectively. 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.