ABSTRACT OBJECTIVE To characterize recent HIV infections among newly diagnosed men who have sex with men and transgender women in Tijuana. METHODS Limiting Antigen (LAg)-Avidity testing was performed to detect recent HIV infection within a cohort of newly-diagnosed men who have sex with men and transgender women in Tijuana. Logistic regression was used to determine characteristics associated with recent infection. A partial transmission network was inferred using HIV-1 pol sequences. Tamura-Nei 93 genetic distances were measured between all pairs of sequences, and the network was constructed by inferring putative transmission links (genetic distances ≤ 1.5%). We assessed whether recent infection was associated with clustering within the inferred network. RESULTS Recent infection was detected in 11% (22/194) of newly-diagnosed participants. Out of the participants with sequence data, 60% (9/15) with recent infection clustered compared with 31% (43/139) with chronic infection. Two recent infections belonged to the same cluster. In adjusted analyses, recent infection was associated with years of residence in Tijuana (OR = 1.5; 95%CI 1.01–1.09), cocaine use (past month) (OR = 8.50; 95%CI 1.99–28.17), and ever experiencing sexual abuse (OR = 2.85; 95%CI 1.03–7.85). DISCUSSION A total of 11% of men newly diagnosed with HIV who have sex with men and transgender women in Tijuana were recently infected. The general lack of clustering between participants with recent infection suggests continued onward HIV transmission rather than an outbreak within a particular cluster.

ABSTRACT OBJECTIVE To characterize recent HIV infections among newly diagnosed men who have sex with men and transgender women in Tijuana. METHODS Limiting Antigen (LAg)-Avidity testing was performed to detect recent HIV infection within a cohort of newly-diagnosed men who have sex with men and transgender women in Tijuana. Logistic regression was used to determine characteristics associated with recent infection. A partial transmission network was inferred using HIV-1 pol sequences. Tamura-Nei 93 genetic distances were measured between all pairs of sequences, and the network was constructed by inferring putative transmission links (genetic distances ≤ 1.5%). We assessed whether recent infection was associated with clustering within the inferred network. RESULTS Recent infection was detected in 11% (22/194) of newly-diagnosed participants. Out of the participants with sequence data, 60% (9/15) with recent infection clustered compared with 31% (43/139) with chronic infection. Two recent infections belonged to the same cluster. In adjusted analyses, recent infection was associated with years of residence in Tijuana (OR = 1.5; 95%CI 1.01–1.09), cocaine use (past month) (OR = 8.50; 95%CI 1.99–28.17), and ever experiencing sexual abuse (OR = 2.85; 95%CI 1.03–7.85). DISCUSSION A total of 11% of men newly diagnosed with HIV who have sex with men and transgender women in Tijuana were recently infected. The general lack of clustering between participants with recent infection suggests continued onward HIV transmission rather than an outbreak within a particular cluster.

Abstract: Objective: To identify correlates of HIV/STI prevalence among 13 cities with varying sizes of female sex worker (FSW) populations and municipal characteristics in Mexico. Materials and methods: FSWs underwent interviews and testing for HIV, syphilis, gonorrhea and chlamydia. Logistic regression explored variations in HIV/STI prevalence. Results: Among FSWs (n=1 092), prevalence across 13 sites was: HIV: 0.4% (range: 0%-1.4%): syphilis: 7.8% (range: 0%-17.2%); chlamydia: 15.3% (range: 5.7%-32.2%); gonorrhea: 2.9% (range 0%-13.8%), and any HIV/STI: 23% (range: 9.9%-46%). Municipalities with high human development scores and a lower municipal marginalization index had higher odds of combined HIV/STI prevalence. After controlling for site-specific variability in municipal characteristics, greater risk of HIV/STIs was associated with lower education, having a spouse diagnosed or treated for an STI, unaffordability of condoms, and having non-Mexican clients. Conclusions: Prevalence of HIV/STIs varies across Mexican municipalities indicating the need for surveillance to identify hotspots for targeted resource allocation.

Resumen: Objetivo: Identificar correlaciones de la prevalencia de VIH / ITS entre 13 ciudades con diferentes tamaños de población de trabajadoras sexuales y características municipales en México. Material y métodos: Las trabajadoras sexuales fueron entrevistadas y recibieron pruebas de VIH, sífilis, gonorrea y clamidia. La regresión logística exploró las variaciones en la prevalencia del VIH/ITS. Resultados: Entre las trabajadoras sexuales (n = 1 092), la prevalencia en 13 sitios fue: VIH: 0.4% (rango: 0-1.4%): sífilis: 7.8% (rango: 0-17.2%); clamidia: 15.3% (rango: 5.7-32.2%); gonorrea: 2.9% (rango 0-13.8%) y cualquier VIH/ITS: 23% (rango: 9.9-46%). Los municipios con altos puntajes de desarrollo humano y menor índice de marginación municipal tuvieron una mayor probabilidad de prevalencia combinada de VIH/ITS. Después de controlar la variabilidad específica del sitio en las características municipales, el mayor riesgo de VIH / ITS se asoció con menor educación, tener un cónyuge diagnosticado o tratado para una ITS, imposibilidad de conseguir condones y tener clientes no mexicanos. Conclusiones: La prevalencia de VIH/ITS varía entre los municipios mexicanos, lo que indica la necesidad de una vigilancia para identificar hotspots para la asignación selectiva.

Abstract: Objective: To identify correlates of HIV/STI prevalence among 13 cities with varying sizes of female sex worker (FSW) populations and municipal characteristics in Mexico. Materials and methods: FSWs underwent interviews and testing for HIV, syphilis, gonorrhea and chlamydia. Logistic regression explored variations in HIV/STI prevalence. Results: Among FSWs (n=1 092), prevalence across 13 sites was: HIV: 0.4% (range: 0%-1.4%): syphilis: 7.8% (range: 0%-17.2%); chlamydia: 15.3% (range: 5.7%-32.2%); gonorrhea: 2.9% (range 0%-13.8%), and any HIV/STI: 23% (range: 9.9%-46%). Municipalities with high human development scores and a lower municipal marginalization index had higher odds of combined HIV/STI prevalence. After controlling for site-specific variability in municipal characteristics, greater risk of HIV/STIs was associated with lower education, having a spouse diagnosed or treated for an STI, unaffordability of condoms, and having non-Mexican clients. Conclusions: Prevalence of HIV/STIs varies across Mexican municipalities indicating the need for surveillance to identify hotspots for targeted resource allocation.

Resumen: Objetivo: Identificar correlaciones de la prevalencia de VIH / ITS entre 13 ciudades con diferentes tamaños de población de trabajadoras sexuales y características municipales en México. Material y métodos: Las trabajadoras sexuales fueron entrevistadas y recibieron pruebas de VIH, sífilis, gonorrea y clamidia. La regresión logística exploró las variaciones en la prevalencia del VIH/ITS. Resultados: Entre las trabajadoras sexuales (n = 1 092), la prevalencia en 13 sitios fue: VIH: 0.4% (rango: 0-1.4%): sífilis: 7.8% (rango: 0-17.2%); clamidia: 15.3% (rango: 5.7-32.2%); gonorrea: 2.9% (rango 0-13.8%) y cualquier VIH/ITS: 23% (rango: 9.9-46%). Los municipios con altos puntajes de desarrollo humano y menor índice de marginación municipal tuvieron una mayor probabilidad de prevalencia combinada de VIH/ITS. Después de controlar la variabilidad específica del sitio en las características municipales, el mayor riesgo de VIH / ITS se asoció con menor educación, tener un cónyuge diagnosticado o tratado para una ITS, imposibilidad de conseguir condones y tener clientes no mexicanos. Conclusiones: La prevalencia de VIH/ITS varía entre los municipios mexicanos, lo que indica la necesidad de una vigilancia para identificar hotspots para la asignación selectiva.