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High burden of chlamydia and gonorrhoea in pharyngeal, rectal and urethral sites among Thai transgender women: implications for anatomical site selection for the screening of STI
  1. Akarin Hiransuthikul1,
  2. Rena Janamnuaysook1,
  3. Thanthip Sungsing1,
  4. Jureeporn Jantarapakde1,
  5. Deondara Trachunthong1,
  6. Steve Mills2,
  7. Ravipa Vannakit3,
  8. Praphan Phanuphak1,
  9. Nittaya Phanuphak1
  1. 1 PREVENTION, Thai Red Cross AIDS Research Centre, Bangkok, Thailand
  2. 2 LINKAGES Thailand FHI 360, Bangkok, Thailand
  3. 3 Office of Public Health, US Agency for International Development, Bangkok, Thailand
  1. Correspondence to Dr Akarin Hiransuthikul, The Thai Red Cross AIDS Research Centre, Bangkok 10330, Thailand; ahiransuthikul{at}


Objective Comprehensive data on Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections to guide screening services among transgender women (TGW) are limited. We studied the burden of CT/NG infections in pharyngeal, rectal and urethral sites of Thai TGW and determined missed CT/NG diagnoses if selected site screening was performed.

Methods Thai TGW were enrolled to the community-led test and treat cohort. CT/NG screening was performed from pharyngeal swab, rectal swab and urine using nucleic acid amplification test. CT/NG prevalence in each anatomical site was analysed, along with the relationships of CT/NG among the three anatomical sites.

Results Of 764 TGW included in the analysis, 232 (30.4%) had CT/NG infections at any anatomical site, with an overall incidence of 23.7 per 100 person-years. The most common CT/NG infections by anatomical site were rectal CT (19.5%), rectal NG (9.6%) and pharyngeal NG (8.1%). Among 232 TGW with CT/NG infections at any anatomical site, 22%–94.4% of infections would have been missed if single anatomical site testing was conducted, depending on the selected site. Among 668 TGW who tested negative at pharyngeal site, 20.4% had either rectal or urethral infections. Among 583 TGW who tested negative at the rectal site, 8.7% had either pharyngeal or urethral infections. Among 751 TGW who tested negative at the urethral site, 19.2% had either pharyngeal or rectal infections.

Conclusion Almost one-third of Thai TGW had CT/NG infections. All-site screening is highly recommended to identify these infections, but if not feasible rectal screening provides the highest yield of CT/NG diagnoses. Affordable molecular technologies and/or CT/NG screening in pooled samples from different anatomical sites are urgently needed.

Trial registration number NCT03580512.

  • chlamydia trachomatis
  • neisseria gonorrhoea
  • transsexual
  • hiv

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  • Handling editor Jackie A Cassell

  • Contributors AH interpreted the data, drafted the manuscript and performed the statistical analysis. TS and JJ coordinated the study and oversaw data management. DT gave advice on statistical analysis and performed statistical analysis. TS, JJ, SM, RV and NP designed and conducted the study. NP advised on the analysis plan. NP and PP led the study. All authors critically reviewed and approved the final draft of the manuscript.

  • Funding This work was supported by LINKAGES (AID-OAA-A-14-00045), which is led by FHI 360 in partnership with IntraHealth International, Pact and the University of North Carolina at Chapel Hill.

  • Competing interests None declared.

  • Patient consent for publication Obtained.

  • Ethics approval The study was approved by the institutional review boards of the Faculty of Medicine, Chulalongkorn University (IRB No 181/57), the Department of Disease Control, Thai Ministry of Public Health (IRB No 9/57–678), and the Provincial Health Offices of Chonburi (IRB No 0032.003/658), Songkhla (IRB No 075/2014) and Chiang Mai (IRB No 0032.002/35859).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as online supplementary information.