Purpose of review Health policy makers aspire to achieve an HIV treatment 'cascade' in which diagnostic and treatment services are accessed early and routinely by HIV-infected individuals. However, migrants and highly mobile individuals are likely to interact with HIV treatment programs and the healthcare system in ways that reflect their movement through time and place, affecting their successful progression through the HIV treatment cascade. We review recent research that has examined the challenges in effective and sustained HIV treatment for migrants and mobile populations. Recent findings Mobility is associated with increased risk of antiretroviral therapy (ART) nonadherence, lost to follow-up, deterioration in CD4 count, HIV-related death, development of drug resistance and general noncontinuity of HIV care. Migrants' slow progression through the HIV treatment cascade can be attributed to feelings of confusion, helplessness; an inability to effectively communicate in the native language; poor knowledge about administrative or logistical requirements of the healthcare system; the possibility of deportation or expulsion based on the legal status of the undocumented migrant; fear of disclosure and social isolation from the exile or compatriot group. Travel or transition to the host country commonly makes it difficult for migrants to remain enrolled in ART programs and to maintain adherence to treatment. Summary Existing public health systems fail to properly account for migration, and actionable knowledge of the health requirements of migrants is still lacking. A large body of research has shown that migrants are more likely to enter into the healthcare system late and are less likely to be retained at successive stages of the HIV treatment cascade. HIV-infected migrants are especially vulnerable to a wide range of social, economic and political factors that include a lack of direct access to healthcare services; exposure to difficult or oppressive work environments; the separation from family, friends and a familiar sociocultural environment. Realizing the full treatment and preventive benefits of the UNAIDS 90-90-90 strategy will require reaching all marginalized subpopulations of which migrants are a particularly large and important group. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Migration Key populations HIV epidemiology Antiretroviral therapy

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