HIV infection in mobile populations: the case of Mexican migrants to the United States.

OBJECTIVE Previous studies have indicated varying rates of HIV infection among labor migrants to the United States of America. Most of these studies have been conducted with convenience samples of farmworkers, thus presenting limited external validity. This study sought to estimate the prevalence of HIV infection and risk factors among Mexican migrants traveling through the border region of Tijuana, Baja California, Mexico, and San Diego, California, United States. This region handles 37% of the migrant flow between Mexico and the United States and represents the natural port of entry for Mexican migrants to California. METHODS From April to December 2002 a probability survey was conducted at key migrant crossing points in Tijuana. Mexican migrants, including ones with a history of illegal migration to the United States, completed an interview on HIV risk factors (n = 1 429) and an oral HIV antibody test (n = 1,041). RESULTS Despite reporting risk factors for HIV infection, none of the migrants tested positive for HIV. CONCLUSIONS Our findings contrast with previous estimates of HIV among labor migrants in the United States that were based on nonprobability samples. Our findings also underline the need for early HIV prevention interventions targeting this population of Mexican migrants.