Transactional sex, HIV and health among young cisgender men and transgender women who have sex with men in Thailand.

Purpose: To examine how recent sex work is identified and the HIV risk factors and service needs among Thai cisgender men who have sex with men (MSM) and transgender women (TGW) who exchange sex.

Methods: MSM and TGW in Bangkok and Pattaya who exchanged sex in the last year (n = 890) were recruited through social media, outreach, and word-of-mouth. Recent sex exchange was based on the primary question, "In the last 30 days, have you sold or traded sex"; secondary questions (regarding income source and client encounters) were also investigated.

Results: Overall, 436 (48%) participants engaged in sex work in the last 30 days; among those, 270 (62%) reported exchanging sex by the primary question, and 160 (37%) based on secondary questions only. Recent sex exchange was associated with gonorrhea, syphilis, discussing PrEP with others, and using condoms, alcohol, methamphetamine, amyl nitrate, and Viagra. Exchanging sex based on secondary questions only was associated with being in a relationship, social media recruitment, less recent anal intercourse, and not discussing PrEP.

Conclusions: Thai MSM and TGW who exchange sex need regular access to HIV/STI prevention, testing, and treatment services, and multiple approaches to assessing sex work will help identify and serve this diverse and dynamic population.