NIDA Community Alert Bulletin - March 25, 1993
National Institute on Drug Abuse

Injection drug use remains a very important risk factor for the transmission of HIV. The AIDS virus can be passed from one person to another when injection paraphernalia are shared. As you know, the virus may be harbored in a variety of items used for drug injection, such as needles, syringes, cotton and "cookers." Needles and syringes, however, remain of paramount concern.

On February 9-10, 1993, the Centers for Disease Control and Prevention, the Center for Substance Abuse Treatment, and the National Institute on Drug Abuse cosponsored a meeting at Johns Hopkins University School of Hygiene and Public Health in Baltimore, Maryland. The workshop reviewed research and current practices on the use of bleach to decontaminate drug injection equipment.

Several papers in the 1980s suggested that household bleach inactivated HIV in vitro (MMWR 1982;31:577-80, Lancet 1984;2:899-900, Journal of Infectious Diseases 1985;152:400-3, and JAMA 1986;255:1887-91). In those studies, the target was cell-free virus or virus in cell culture. Bleach soon became the standard for use in needle hygiene programs, and small bottles of bleach were distributed to injecting drug users (IDUs) by outreach workers throughout the country. Bleach bottles became a point of contact with drug users out-of-treatment, and their distribution became a vehicle to provide AIDS education and a recruitment tool for drug abuse treatment.

However, more recent data have raised new questions about the efficacy of bleach cleaning. These new findings were summarized at the Baltimore meeting in February. One study found that bleach was more effective than most other readily available solutions, such as alcohol and hydrogen peroxide, but not as effective against HIV in blood as it was against HIV in a cell-free state or in cell culture (Flynn et al., Sixth International Conference on AIDS, 1990, Abstract S.C.761;3:279). Another examined the HIV seroconversion rates among a cohort of injecting drug users in Baltimore and compared those reporting use of disinfectants all the time versus those who denied ever using disinfectants to clean needles and syringes. No significant difference in HIV infection incidence between disinfectant users and nondisinfectant users was found (Vlahov et al., Epidemiology 1991;2:444-6).

Contoreggi et al., NIDA, found that a 10 percent dilution of household bleach (0.525% sodium hypochlorite) was not effective in removing blood from syringes using a 6-second cleaning with bleach, followed by two 6-second rinses with water. Clotted blood was more difficult to clean than fresh blood (VIII International Conference on AIDS, 1992, Abstract PoC 4280;2:C291). Dr. Contoreggi also observed that bleach may initially enhance clot formation when mixed with blood, which may hinder blood removal and HIV inactivation (unpublished data). Still another study in Miami found that full-strength household bleach (5.25% sodium hypochlorite, e.g., brand name Clorox) was an effective inactivator of pelleted HIV at exposures of 30 seconds or greater, whereas a 10 percent dilution of household bleach (0.525% sodium hypochlorite) was effective only after exposures of 2 hours [Shapshak et al., J AIDS 1993;6:218-9 (letter)]. Gleghorn et al., videotaped drug users conducting mock needle and syringe cleaning and found that more than 80 percent of 161 subjects used bleach for less than 30 seconds when cleaning syringes, although they reported cleaning for longer periods of time (unpublished data).

The sum of this research indicates that use of bleach is an imperfect approach to eradicate or inactivate HIV from injection equipment. We must continue to strengthen our efforts to help IDUs cease to use drugs. Those who do continue to inject drugs must be encouraged to never share injection equipment and be aware that the cleaning of needles and syringes between uses is an imperfect way to prevent HIV infection.

The next two pages list recommendations I would like to propose to help drug users understand how to decrease their risk of HIV infection.

Please feel free to call me at (301) 443-6480 or Dr. Harry Haverkos, Director, Office on AIDS, NIDA, at (301) 443-6697 to discuss these findings and recommendations.

Sincerely,

Richard A. Millstein Acting Director

Proposed Recommendations to Prevent HIV Transmission by Sharing Drug Injection Equipment

All drug abusers should be aware of the potential for acquiring HIV infection and AIDS from sequentially using (sharing) injection equipment and paraphernalia and through sexual activity. [NOTE: For more specific recommendations regarding sexual transmission of HIV, see MMWR 1986;35:152-5.]

Persons with a negative HIV-antibody test should be counseled to reduce their risk of acquiring HIV infection through sharing injection equipment by the following means.

* Abstain from any further use of drugs by injection. This eliminates any new risk of bloodborne infections. Drug abuse treatment should be sought to aid in stopping drug use.

* Do not share injection equipment with anyone. This further protects the drug user from contracting HIV infection. Care should be taken not only with needles and syringes, but also with cotton balls, cookers, wash bottles, or any other materials possibly containing blood. [Note to Policymakers and other Public Health Officials: Review your local laws and regulations concerning needle/syringe availability and paraphernalia possession. Needle/syringe exchange programs may provide another means of providing sterile equipment to users and decreasing sequential use of injection equipment by addicts; however, the risks and benefits of such programs are still under study.]

* If you continue to share injection equipment, disinfect between uses. While it is not foolproof, boiling needles and syringes for 15 minutes is one way to sterilize equipment between uses; however, boiling plastic equipment may alter the shape and utility of the syringes. Cleaning injection equipment with disinfectants, such as bleach, does not guarantee that HIV is inactivated. DISINFECTANTS DO NOT STERILIZE EQUIPMENT. However, consistent and thorough cleaning of injection equipment with disinfectants such as bleach should REDUCE transmission of HIV if equipment is reused or shared.

* To maximize the effectiveness of cleaning, needles and syringes should be flushed with water, preferably soon after use, before blood has time to clot in the needle and syringe. Continue flushing until the equipment is at least visibly clear of blood and debris. The use of soapy water and agitating (tapping, shaking or "plucking") the equipment while cleaning may be helpful in removing blood and debris. The equipment should then be FILLED with full-strength household bleach for at least 30 seconds of contact before again rinsing with water. Even apparently clean equipment should be bleached before use unless it is known to be sterile. Bleach, which is highly corrosive, may alter the usefulness of the equipment.

Infected persons should be counseled to prevent further transmission of HIV by the following means:

* Inform prospective drug-using partners and sexual partners of his or her infection, so they can take appropriate precautions. Clearly, abstaining from drug injection and sexual activity with another person is one option that would eliminate any risk of HIV transmission by those routes.

* Protect a partner during any drug use by taking precautions, as suggested above. Since reinfection and/or infection with another strain of HIV may contribute to disease progression, HIV-infected drug users should refrain from reusing or sharing injection equipment to protect their own health as well as that of others.
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