Abstract
Presently, the HIV-AIDS epidemic is the stage of significant developments of therapeutic procedures and vaccine experiments. This situation re-introduces, with great accuracy, the problem of recruitment, participation and follow-up of healthy and ill volunteers in scientific experiments. The present paper aims to describe the social representations of individuals who refuse to take part in therapeutic experiments against the HIV immunisition. The paper focuses on potential volunteers, looking at the supposed difficulties they have in understanding the messages directed to them. We suggest that the difficulties presented by “non-volunteers” through their representations of vaccine substances, reflect their subjective position toward what they consider the “world of AIDS”, as well as to Medicine and Science.