Sex Worker Leadership in Responding to HIV and Promoting Human Rights   299
points to the importance of continued, long term funding that is focused as much on HIV prevention actions as strengthening the capacity of the NGOs that provide a basis for ongoing communication and addressing future concerns and issues facing sex workers. The role of the broader social, political, and legal climate in shaping the scope and nature of sex worker participation in HIV prevention is also clear through review of the cases. The sex worker based mobilization and organization approaches notably emerged in contexts characterized by labor rights and citizens rights movements, i.e., Kolkata and Brazil. While the lack of such a political and social climate in Thailand at the time of the 100% condom program cannot be conclusively said to have impeded such a response, findings suggest the need to consider the broader social and political climate in planning efforts to promote mobilization and participation among sex workers. Settings of ongoing collectivization around labor rights or other topics may catalyze the impact of investment in sex worker participatory efforts; while climates of civic disengagement, distrust of government and protracted disempowerment may slow the process of cultivating a participatory model. These examples illustrate the need for consideration of the broader social and political climate in planning national and international responses to HIV among sex workers. Finally, among the lessons learned from the early responses to HIV among sex workers are that the benefits are greatest to those who can participate to the fullest extent (Kerrigan, Telles et al. 2008). Even within climates characterized by overt structural changes in the forms of mobilization efforts to decrease discrimination, internalized stigma and overt discrimination pose formidable barriers to accessing HIV prevention (Kerrigan, Telles et al. 2008; Blankenship, Burroway et al. 2010). Thus the needs of the most vulnerable sex workers must be prioritized, and the limitations of both government-led and mobilization approaches recognized. The social conditions that prompt involvement in sex work are often grim, including poverty, family breakdown and abuse, low levels of education, humanitarian emergencies and post conflict situations (UNAIDS 2009). These factors may contribute to their stigma and isolation and simultaneously promote HIV risk. Because those in greatest need may be least able to participate based on documentation concerns, language barriers, and fears and instability put forth by conditions of mass migration, natural disaster and protracted civic conflict, vigilance is needed to ensure inclusion of these highest risk groups of sex workers. Findings from the cases reviewed also illustrate gaps and provide necessary direction for the next generation of comprehensive structural responses to HIV among sex workers. Although clients constitute a primary element of the broader context of sex work, client-oriented prevention efforts remain