[How should research protocols be implemented in the field?]

The hepatitis issue is a major public health concern, especially the widespread expansion of HCV infection among drug users. Prevention is focused on the prevention of risky behaviors (injection, needle and material sharing). Research is needed to improve our comprehension of the relatively low efficiency of actions taken in this field. We need better knowledge of the users' present practices, patterns of use and contexts of consumption but also about their own knowledge or beliefs about this infection. These qualitative studies should be conducted with a direct contact with users in the field: streets, drug scenes, low threshold structures, addiction therapy centres, physicians networks... These are not easy fields for study because of different reasons linked with the structures per se but also with the particular public involved. Some specific difficulties are presented as well as some means of coping with them. Experience has shown that it is possible to handle these issues and to conduct such studies.