E PIDEMIOLOGY High Mobility and HIV Prevalence Among Female Market Traders in East Africa in 2014 AQ : 1 Carol S. Camlin, PhD, MPH,*†‡ Alison M. El Ayadi, ScD,*† Zachary A. Kwena, PhD,§ Willi McFarland, PhD, MPH,‡k Mallory O. Johnson, PhD,‡ Torsten B. Neilands, PhD,‡ Elizabeth A. Bukusi, MBChB, MMed, MPH, PhD,§ and Craig R. Cohen, MD, MPH*† Background: The contribution of women’s mobility to the HIV/ AIDS epidemic in Africa is poorly understood, despite women’s high mobility and evidence that it is associated with higher-risk sexual behavior. We sought to measure levels of mobility, HIV prevalence, and related risk behaviors among female traders in Kisumu, Kenya. Methods: We used global positioning system mapping to develop a probability-based sample and recruited 305 female market traders for participation in a survey and voluntary HIV counseling and testing in 2014. We estimated HIV prevalence and fitted logistic regression models to measure associations between mobility, risk behaviors, and HIV infection. Results: HIV prevalence was 25.6% (95% confidence interval: 21.0 to 30.8); 11.5% had migrated (changed residence, over county, or national boundary) in the past year and 39.3% in the past 5 years. More than one-third (38.3%) spent nights away from main residence in the past month, with 11.4% spending more than a week away. Multiple partners were reported by 13.1% of women in the last year; 16% of married women reported a concurrent partnership. Mobility was not significantly associated with HIV prevalence, although recent short-term mobility was significantly correlated with higher numbers of sexual partners in the past year. Conclusions: Female market traders were highly mobile, and HIV prevalence among traders was higher than in the general population of women of reproductive age in Kisumu (15.3% in 2013), and Received for publication June 24, 2016; accepted November 9, 2016. From the *Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Francisco, San Francisco, CA; †Bixby Center for Global Reproductive Health, University of California, San Francisco, San Francisco, CA; ‡Center for AIDS Prevention Studies, University of California, San Francisco, San Francisco, CA; §Centre for Microbiology Research, Kenya Medical Research Institute, Kwale, Kenya; and kDepartment of Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, CA. AQ : 2 Supported by a grant from the National Institutes of Health, University of California, San Francisco-Gladstone Institute of Virology & Immunology Center for AIDS Research (UCSF-CFAR), P30-AI027763. C.S.C. was supported by a Research Scientist Development Award from the National Institute of Mental Health (NIMH), K01MH093205. M.O.J. was supported by Grant Number K24DA037034. AQ : 3 The authors have no conflicts of interest to disclose. Correspondence to: Carol S. Camlin, PhD, MPH, Department of Obstetrics, Gynecology & Reproductive Sciences, University of California, San Francisco, 550 16th Street, 3rd Floor (UCSF Mailcode 1224), San Francisco, CA 94158-2549 (e-mail: carol.camlin@ucsf.edu). Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved. Nyanza Province, Kenya (16.1% in 2012). High HIV prevalence and risk behavior among women in this study warrant accelerated attention to HIV prevention and care needs of mobile women, including market traders. Key Words: HIV, migration, mobility, female migrants, East Africa, Kenya (J Acquir Immune Defic Syndr 2016;00:1–8) INTRODUCTION The contribution of population mobility to the HIV epidemic in sub-Saharan Africa is well documented; the spread of HIV followed the corridors of population move- ment. 1–10 However, mobility and HIV research has tended to focus on risks to male labor migrants and their partners, or migrants overall, often failing to measure the risks to women through their direct participation in migration. 3,11–17 Yet across the region, women’s levels of participation in internal migration (ie, changes in residence within national bound- aries) and short-term mobility (frequent travel without a permanent change in residence) have now met or exceeded those of men. 18–22 Moreover, the few studies which have examined HIV risks to female migrants found higher risk behavior and HIV prevalence among migrant compared with nonmigrant women, 23–30 and suggest differential HIV risks associated with mobility for women versus men. 30 The literature on migration has highlighted the cen- trality of sex to understanding migration decision-making, determinants, and consequences. 31–33 Indeed, in Southern and East Africa, mobility patterns differ for men and women, and have important implications for HIV risk; women have tended to migrate shorter distances to informal settlements or regional towns, retaining ties to rural homes and returning frequently, whereas men have migrated over longer distances to urban areas, and have been less likely to return to households of origin. 18,34 Engagement in different corridors of mobility and destinations likely exposes female migrants to sexual networks and geographic areas of different HIV prevalence compared with males, resulting in different probabilities of infection for each given sexual act. 35 Population-based studies report HIV prevalence in informal settlements and periurban areas to be twice as high compared with urban and rural areas. 5,28,36 Thus, high female mobility may contribute to the sustained, high prevalence of HIV in Southern and East Africa, enabling J Acquir Immune Defic Syndr Volume 00, Number 00, Month, 2016 www.jaids.com | Copyright O 2016 Wolters Kluwer Health, Inc. 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