Knowledge of HIV serostatus and preventive behaviour among European injecting drug users. The European Community Study Group on HIV in Injecting Drug Users.

OBJECTIVE: To study the effect of knowledge of HIV serostatus on behaviour for preventing the acquisition or transmission of HIV among European injecting drug users (IDU).
METHODS: Data on behaviour and prior knowledge of HIV status were gathered during a multicentre cross-sectional survey of 200 European IDU recruited in 12 European countries in 1990. The respective proportions of IDU who (1) used condoms, (2) did not give their used injecting equipment to other IDU and (3) injected drugs safely (ether did not re-use other IDU's equipment or re-used it only after disinfection with bleach, alcohol or boiling water during the 6 months preceding interview were compared according to whether they knew their HIV serostatus for at least 6 months prior to interview.
RESULTS: In comparison with IDU who had never been tested, IDU who knew that they were HIV-seropositive were more likely to always use condoms [rate ratio (RR) = 3.1; 95% confidence interval (CI), 2.3-4.2] and never gave their used equipment to other IDU (RR = 1.3; 95% CI, 1.2-1.5), but did not differ with regard to safe injecting practices (RR = 1.0; 95% CI, 0.9-1.1). Compared with IDU who had never been tested, IDU with a negative test tended to inject drugs safely more often (RR = 1.1; 95% CI, 1.02-1.2). There was no significant difference in condom use (RR = 0.7; 95% CI, 0.5-1.1).
CONCLUSION: These results indicate that the knowledge of HIV serostatus may help to reduce HIV transmission from HIV-positive IDU to others through safer injecting and sexual behaviour. However, for HIV-negative IDU safer injecting behaviour appears to be better accepted than safer sexual behaviour.