The main purpose of the CoDISEN cohort study is to propose a model of prevention and care for HIV and viral hepatitis adapted to the needs of people who inject drugs (PWID) in Dakar, Senegal.

THE UNODC estimated the number of consumers of injectable drugs at 1,02 millions in 2012 in Africa among which 12,1 % lived with HIV. Prevalences of HIV, chronic hepatitis C and B among people who inject drugs remain little documented in Sub-Saharan Africa. The transmission of HCV in Africa is mainly hospital-borne, bound to a precarious transfusional and therapeutic safety. However, the transmission by intravenous drug use emerges as a new stake in public health in urban areas. The report of a strong HIV prevalence in the population of PWID in the sub-region ( for example, In 2007, in the Cape Verde, prevalence of the HIV was 14 % in emprisoned PWID against 0,8 % in the general population) contributed to assert the reality of the use of intravenous drugs in the region and the vulnerability of this population. Senegal, a country with an concentrated HIV epidemic [0,5 % prevalence in 2012, WHO source] is the first country of western Africa to have measured prevalence of HIV (5,2 %), HBV (7,9 %) and HCV (23,3 %) in PWID (Study ANRS 12243). In view of these results, the Senegalese authorities introduced from October, 2011 in Dakar, activities of harm reduction by means of a mobile team of social workers and mediators allowing individual and collective activities of prevention, needle exchange program, references for care and follow-up, as well as a opioid substitution program in a methadone center (CEPIAD) located in Dakar, first of its kind in Western Africa. The objective of the present research project thus is to estimate the impact of a strategy of " test and treat " of HIV and harm reduction initiatives on the prevalence and incidence of HIV, HBV and HCV infections in an population of injectable drug consumers followed in the methadone center ( CEPIAD) of Dakar, Senegal

Inclusion Criteria:

• being aged greater than or equal to 18 years or emancipated minor,
• Being or have been an injecting drug user and followed at the CEPIAD (methadone program)
• Living in the Dakar region for at least three months,
• Consenting to the study after individual information.

Exclusion Criteria:

• Mental impairment making it difficult or impossible to consent to the study.

Population of active injecting drug users who are seeking care at the CEPIAD, Dakar, Senegal.

IPD that can be shared include study protocol, statistical analysis plan, inform consent form and anonymized database

Duration of the study and 2 years after study closure

Any sharing of information related to the study must be approved by the Scientific committee and the sponsor.