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

Abstract

ObjectiveComprehensive 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.MethodsThai 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.ResultsOf 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.ConclusionAlmost 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 numberNCT03580512.

Sexually transmitted infection screening, prevalence and incidence among South African men and transgender women who have sex with men enrolled in a combination HIV prevention cohort study: the Sibanye Methods for Prevention Packages Programme (MP3) project

“…It might be the case that those at the highest risk of rectal infections were more likely to accept rectal screening; however, there were no differences in rectal screening acceptance based on reporting anal intercourse in the past three months. A recent study of Thai TGW found that rectal screening produced the highest yield of positive NG/CT infections [10], implying that rectal screening will be vitally important to reduce NG/CT incidence and prevalence. Future studies should assess reasons for refusal of rectal screening.…”

“…Current STI screening recommendations in South Africa are based on syndromic surveillance and management [6]. Much of the STI screening that is conducted with MSM and TGW is by blood or urine specimens, but in some studies of MSM and TGW, there is considerably higher prevalence of rectal STIs than urethral STIs or syphilis [7‐9] and multi‐site screening has been shown to substantially increase the yield of positive tests [10].…”

Epidemiology of gonorrhoea: a global perspective

“…Whereas the gonorrhoea positivity of urogenital specimens ranged from 0.1% (among 764 women from drop-in centres in Thailand) to 2.8% (among 406 STI clinic attendees at multiple sites in the USA), positivity of pharyngeal specimens ranged from 3.5 to 37.3% across studies (with positivity of 8.1-9.8% in the two largest studies from Thailand and the USA). [72][73][74][75] Positivity among rectal specimens ranged from 6.3 to 43% (9.6-11.8% in the Thailand and USA studies). [72][73][74][75][76] Two studies that did not mention the anatomic site of specimen collection found a prevalence among transgender women of 2.1% (among 63 young adults in the USA) and 4% (among 77 STI clinic attendees in Australia).…”

“…[72][73][74][75] Positivity among rectal specimens ranged from 6.3 to 43% (9.6-11.8% in the Thailand and USA studies). [72][73][74][75][76] Two studies that did not mention the anatomic site of specimen collection found a prevalence among transgender women of 2.1% (among 63 young adults in the USA) and 4% (among 77 STI clinic attendees in Australia). 77,78 Although data on transgender men are even more scarce, available data hint at high gonorrhoea prevalence.…”

Sexually Transmitted Infections Treatment Guidelines, 2021

“…Bacterial STI prevalence varies among transgender women and is based largely on convenience samples. Despite limited data, international and U.S. studies have indicated elevated incidence and prevalence of gonorrhea and chlamydia among transgender women similar to rates among cisgender MSM (346)(347)(348). A recent study using data from the STD Surveillance Network revealed that the proportions of transgender women with extragenital chlamydial or gonococcal infections were similar to those of cisgender MSM (349).…”