Introduction Understand the circularity of information and its role or relation with the advancement of the HIV/AIDS epidemic among young people in Brazil; Discuss the role of knowledge in this context of great access and circulation of information, especially among young people.

Methods From authors such as Giddens, Casttels, Spink and Goffman, we discuss the circularity of networked knowledge and its implications and influence on the behaviour of young people in vulnerability. From the theoretical discussion, interviews were conducted with 8 HIV positive and seronegative youths with the objective of identifying the sources of information they access about HIV/AIDS, in order to answer the following questions: What knowledge circulates? Where do they come from? Where are they going? How do they circulate? What is the purpose? What is the real impact of the information? What subjects add to it? Subsequently, the interviews were transcribed and submitted to the Thematic Content Analysis.

Results We identified three themes addressed by young people when questioned about information and knowledge they have about HIV/AIDS: the exchange of information in network media (internet, smarthphones) as the main way of circulating knowledge; The discourse of risk and its weight in the decisions taken (whether they are to ”risk” or ”protect”); And the idea of vulnerable youth and youth empowered by accessible and available information. Knowing is not enough to prevent, because several other factors interfere in the decision to adopt a protective attitude towards the infection. Information can also contribute to the inverse effect; by the sense of empowerment it gives the youth.

Conclusion It is necessary to understand, create and/or identify new ways of ”taking care”, that consider the dynamics of the circularity of knowledge and undo the myth that ”knowing is sufficient to prevent”, from the identification of other factors circulating in the dynamics.