Migration, Sexual Behavior, and Gender Identity: Triple Vulnerability to the Presence of HIV and Other Sexually Transmitted Infections.

Sexually transmitted infections (STIs) caused by HIV, Treponema pallidum (syphilis), and herpes simplex virus type-2 (HSV-2) are interrelated. Due to a mosaic of political, social, and economic situations, migrants are susceptible to acquiring STIs. The objective of this study was to estimate the seroprevalence of HIV, syphilis, and HSV-2 in migrants in transit in Tapachula, Chiapas, Mexico and to analyze their associated factors. A cross-sectional study was conducted between 2021 and 2022 in migrant care centers in the city of Tapachula, Chiapas, Mexico. A behavioral questionnaire was administered and a blood sample was collected. Immunological tests were performed to detect HIV, syphilis, and HSV-2. Associated factors were determined through multivariate binary logistic regression models. A total of 655 migrants participated, of which 51.5% were males. The seroprevalence of HIV, syphilis, and HSV-2 was estimated to be 8.9%, 10.5%, and 33.3%, respectively; for HIV and syphilis, the seroprevalence was higher among males than among females (p < 0.05), especially among men who have sex with men (MSM) and transgender women. A previous history of STIs, genital lesions, age at sexual debut, years of sexual activity, and having sex with members of the same sex were associated factors. In key groups, such as MSM and transgender women, the social and environmental contexts to which they are exposed as migrants, in interaction with clinical and behavioral factors, act as cumulative layers of vulnerability that increase the odds of migrants in transit to acquiring HIV, syphilis or HSV-2.