Objectives: To describe and estimate the frequency of different types of drug preparation and injection practices that could result in the transfer of blood and blood-borne infections among injection drug users (IDUs).
Methods: We analyzed data from interviews administered to 12,323 active IDUs recruited from 19 sites in the United States. The interviews ascertained drug-related behaviors during the previous 30 days.
Results: 31.9% of IDUs reported that they engaged in the use of both needle/syringes and cookers/cotton/water previously used by another IDU; 8.6% engaged only in the use of needle/syringes previously used by another IDU; 17.5% engaged only in the use of cookers/cotton/water previously used by another IDU; and 42.0% reported using neither needle/syringes nor cookers/cotton/water previously used by another IDU. Only 12.6% reported use of new (never-used) needle/syringes. The 3935 IDUs who used both needle/syringes and cookers/cotton/water that had been previously used by another IDU had more than 311.000 potential exposures to blood-borne infections from these high-risk practices in 30 days; about 64% of these exposures were from multiperson use of cookers/cotton/water.
Conclusions: Programs to limit parenteral transmission of HIV and other blood-borne infections among IDUs must consider all drug preparation and injection practices that could allow transfer of blood and blood-borne infections among IDUs.