Needle sharing with known and diagnosed human immunodeficiency virus-infected injecting drug users.

The annual number of reported cases of human immunodeficiency virus (HIV) infection among injecting drug users (IDUs) in Sweden has been about 20 for more than 5 y, but in 2001 36 new cases were reported. Risk behaviour for contracting HIV infection was studied in 21 of 24 identified and evaluable IDUs with diagnosed HIV infection in the metropolitan area of Stockholm in 2001 and in 23 of 30 evaluable consecutive controls. HIV status was associated with general needle sharing (p = 0.04) and needle sharing with an HIV-positive individual (p = 0.0001), despite extensive information on possible transmission routes for HIV. These results indicate that efforts for reducing transmission of HIV should focus on HIV-negative and HIV-positive individuals with risk behaviour.