RESUMEN
This article revisits the history of HIV prevention for gay and other men who have sex with men in relation to public health policy and the role of LGBT and AIDS-related social movements in Brazil. An interpretive study was undertaken informed by philosophical and phenomenological hermeneutics. It included interviews with policymakers, researchers and activists involved in HIV and AIDS, especially HIV prevention among gay and other men who have sex with men. Prevention initiatives were analysed with a focus on the social and programmatic aspects of vulnerability to HIV, and advances and setbacks in the Brazilian response to the epidemic. The recent crisis in HIV prevention triggered by a growing conservatism in Brazilian politics and the current government's LGBT-phobia pose barriers that compromise issues of profound importance with regards to policy on HIV and AIDS: namely, engagement with human rights and social participation.