Transmission of AIDS HIV Virus Through Needle Sharing

Injection drug use (IDU) follows sexual activity as the highest risk behavior for the transmission of HIV in the U.S. and Europe. In 1992, IDU accounted for nearly one fourth of all existing cases of AIDS in the U.S. Moreover, people who use injection drugs comprised more than 50% of all new cases of AIDS in the U.S. in 1992 (Centers for Disease Control, 1993b).

IDU generally involves a multistep process. A powdered form of a drug is placed inside a "cooker," usually a spoon, bottle cap, or similar readily available item. Water is added and the solution is heated over a flame. Next the solution is drawn up into a syringe, frequently through a piece of cotton to filter out undissolved impurities. The needle is then inserted into a vein. Blood is drawn up into the syringe and mixed with the drug solution before it is injected into the vein. Finally, the equipment is rinsed with water before the next user repeats the process.

Five of the items described in this process can be the source of HIV transmission: the syringe, needle, "cooker," cotton, and rinse water. Contaminated blood can be left in the syringe or on the needle. Blood can be pushed out of a used syringe into the cooker before the heated solution is drawn up. Water is often added to used cotton in an effort to squeeze out any drug that was caught there in the straining process; infected blood can be squeezed out during this process. Finally, the reuse of contaminated rinse water can result in HIV transmission.

The common phenomenon of sharing drug paraphernalia causes HIV transmission among users. Injection equipment is shared primarily because possession of it is a crime in many states, but also because many users cannot afford it. In some communities injection equipment is rented in "shooting galleries," where drug users gather. Needles are sometimes used and reused until they become too dull to penetrate the skin. Widespread sharing of paraphernalia means that when HIV enters a drug-using community, it tends to spread rapidly, resulting in high rates of infection.

Prevention of Injection Drug Use AIDS HIV Transmission

Transmission of HIV during drug use can be prevented by not sharing injection equipment. To discourage multiperson use of needles, needle exchange programs have been tried in a number of locations (Martinez, 1992). Users are able to bring in used needles and syringes and exchange them for clean ones. Objections to such programs have been raised, however, by those who feel that they encourage the use of illegal drugs. An increase in the quality and quantity of drug treatment programs can also reduce the spread of HIV by reducing the number of people who are injecting drugs.

For individuals who continue to inject drugs and to share drug paraphernalia, the risk of HIV transmission can be reduced by cleaning the equipment between use. Although numerous cleaning products have been examined, full-strength bleach has been found to be the most effective (Flynn et al., 1994). Bleach can be drawn into needles and syringes to clean them. The cooker should also be rinsed with bleach, as heating it between uses may not kill the virus.

In addition, if the needle and the syringe are clean, there is no risk of the cooker becoming infected. Cotton should be disposed of between uses. To prevent accidental injection of the bleach, equipment should be flushed or rinsed with clean water following disinfection. Although these steps effectively reduce the risk of HIV transmission, it is safer still to always use a sterile needle and syringe. Furthermore, bleach used improperly is likely to prove ineffective against HIV. To be truly effective, the bleach should be undiluted and the needle and syringe should be exposed to the bleach for at least 30 seconds.

Last updated Jan 4/07