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Knowledge and Practices Among Injecting-Drug Users of Bleach Use for Equipment Disinfection -- New York City, 1993

Sharing (i.e., multiperson use) of drug-injection equipment among injecting-drug users (IDUs) is a major risk factor in the transmission of human immunodeficiency virus (HIV) and other bloodborne pathogens. Abstaining from injection of drugs eliminates this risk; disinfection of needles and syringes with household bleach can reduce this risk. Because studies suggest the effectiveness of bleach disinfection may be limited, the March 1993 National Institute on Drug Abuse (NIDA) Community Alert Bulletin included recommendations that IDUs who do not stop injecting and sharing injection equipment use full-strength household bleach and keep the bleach in contact with the equipment for at least 30 seconds (1). To determine whether these new recommendations had been disseminated effectively to IDUs, the knowledge of bleach use for disinfection of drug-injection equipment among IDUs participating in a NIDA-sponsored New York City cohort study was assessed during August-December 1993. This report presents data about knowledge of bleach use for disinfection among persons who reported injecting drugs at least once during the 3-6 months preceding the interview.

During September 1991-December 1993, cohort members were recruited originally from methadone-maintenance treatment programs (MMTPs) in Manhattan and through flyers and word-of-mouth in Manhattan communities with large numbers of out-of-treatment IDUs. During August-December 1993, 696 cohort members were interviewed during scheduled study visits; 367 (53%) who stated they had not injected drugs during that period and 39 (6%) who were not asked about bleach were excluded from this analysis. At the time of the interview, 304 (83%) of those excluded because they had not injected drugs were enrolled in MMTPs, and eight (2%) were in other types of drug treatment. Respondents were asked, "Should bleach be mixed with water to clean works?" "If yes, how much water are you supposed to mix in with the bleach?"; and "How long do you need to leave the bleach in the syringe in order to kill the AIDS virus?" Respondents also were asked whether they had "injected {drugs} with used needles or shared needles with anyone."

Of the 290 active IDU respondents, 232 (80%) were male; the mean age of all persons interviewed was 40 years (range: 22-66 years). Most (230 {79%}) respondents were enrolled in MMTPs at the time of interview; five (2%) were in other types of drug treatment; and 55 (19%) were not in treatment. Overall, 150 (52%) reported average injection frequency of at least once per week during the 3- 6 months preceding the interview. The primary drugs injected were heroin, cocaine, or a combination of heroin and cocaine. Needle-exchange programs were reported as the primary source of injection equipment for 118 (41%) during the 3-6 months preceding the interview.

Of the 290 respondents, 173 (60%) knew that full-strength bleach should be used to clean used needles, compared with 90 (31%) who thought bleach should be mixed with water; 27 (9%) did not know what strength bleach should be used. One hundred seventy-one (59%) respondents knew that needles and syringes must be in contact with bleach for at least 30 seconds. Approximately one third (102 {35%}) responded correctly to both of these questions.

Of 60 persons who reported sharing injection equipment during the preceding 3-6 months, 38 (63%) did not answer both questions correctly. Forty-five (75%) reported either not using bleach or using bleach inconsistently. Four (7%) of those who reported sharing injection equipment responded correctly to both questions and reported always using full-strength bleach.

Correct bleach use knowledge did not differ substantially for sex; age; methadone-treatment status; educational level; and recent needle exchange, needle sharing, and bleach use.

Reported by: M Marmor, PhD, H Wolfe, MS, S Titus, MPH, New York Univ Medical Center, Dept of Environmental Medicine; DC Des Jarlais, PhD, Beth Israel Medical Center, New York. Behavioral and Prevention Research Br, Div of Sexually Transmitted Diseases and HIV Prevention, National Center for Prevention Svcs; Office of the Associate Director (HIV/AIDS), Office of the Director, CDC.

Editorial Note

Editorial Note: The findings in this report indicate that only one fifth of the active IDUs reported sharing injection equipment. However, of those who did share, only one fourth used bleach consistently and, of all the active IDUs, only one third knew both recommendations for correct bleach use, regardless of whether they shared injection equipment or used bleach. Because of inconsistent use and incomplete knowledge, active IDUs who reuse syringes that have been used by other IDUs are at high risk for HIV infection.

The findings of this study are subject to at least three limitations. First, these findings may not be generalizable to other IDUs in New York City or in other U.S. cities. Second, because the data were gathered 5-9 months after the NIDA bulletin was issued in March 1993, knowledge levels of IDUs since then may have increased. Finally, the sample size was adequate to detect only large effects of many characteristics on knowledge of correct bleach use for disinfection.

Because IDUs do not always use sterile equipment, since the mid-1980s HIV-prevention programs for IDUs in the United States have recommended using bleach for disinfection of drug-injection equipment previously used by another person to reduce the possibility of HIV transmission. Bleach was recommended based on its widespread availability, low cost, and ability to inactivate HIV (2).

Recent findings have indicated three limitations in the effectiveness of using bleach: 1) the presence of blood or other organic material in the equipment can reduce the effectiveness of bleach (3); 2) there appears to be a minimum contact time needed for bleach to inactivate HIV (4); and 3) many IDUs do not follow recommendations for bleach use for disinfection (5). As a result of these limitations, two national bulletins were issued in early 1993 (1,6) describing disinfection procedures that would increase the likelihood of disinfection. The provisional recommendations included prebleach washing of the syringe to remove organic material, use of full-strength bleach, and presence of bleach in the syringe for at least 30 seconds.

HIV-prevention programs that target drug users should inform IDUs 1) not to inject drugs; 2) if they do inject, to use new, sterile needles and syringes for every injection; and 3) if they cannot use sterile equipment, to disinfect the equipment following the recommendations for bleach disinfection. The availability of effective drug-treatment programs and sterile injection equipment are HIV-prevention priorities to assist IDUs who will not or cannot stop injecting drugs (7).


  1. Millstein R. Community alert bulletin. Rockville, Maryland: US Department of Health and Human Services, Public Health Service, Alcohol, Drug Abuse, and Mental Health Administration, National Institute on Drug Abuse, March 25, 1993.

  2. Martin LS, McDougal JS, Loskoski SL. Disinfection and inactivation of human T lymphotrophic virus type III/lymphadenopathy-associated virus. J Infect Dis 1985;152:400-3.

  3. Flynn N, Jain S, Keddie E, et al. Bleach is not enough: giving IV drug users a choice of disinfectants when they share needles and syringes {Abstract}. Vol 3. VI International Conference on AIDS, San Francisco, June 20-24, 1990:279.

  4. Shapshak P, McCoy CB, Rivers JE, et al. Inactivation of human immunodeficiency virus-1 at short time intervals using undiluted bleach {Letter}. J Acquir Immune Defic Syndr 1993;6:218-9.

  5. Gleghorn AA, Doherty MC, Vlahov D, et al. Insufficient bleach contact time during syringe cleaning among injecting-drug users (IDUs) {Abstract}. Vol 2. IX International Conference on AIDS/IV STD World Congress, Berlin, June 6-10, 1993:872.

  6. CDC/Center for Substance Abuse Treatment/National Institute on Drug Abuse. HIV AIDS prevention bulletin. Atlanta: US Department of Health and Human Services, Public Health Service, CDC, April 19, 1993.

  7. Lurie P, Reingold A. The public health impact of needle exchange programs in the United States and abroad. Vol 1. San Francisco: Institute for Public Health Studies, 1993.

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