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U.S. Department of Health and Human Services

Archival Content: 1999-2005

Letters about Injection Drug Users and HIV Prevention Issues

HIV/AIDS Prevention Bulletin

April 19, 1993

Dear Colleague:

This letter contains new information on the role of bleach in human immunodeficiency virus (HIV) prevention programs for injecting drug users (IDUs). Based on recent research, bleach disinfection should be considered as a method to reduce the risk of HIV infection from re-using or sharing needles and syringes (and other injection equipment) when no other safer options are available. Sterile, never-used needles and syringes are safer than bleach-disinfected, previously used needles and syringes. This letter provides some recommendations on how bleach disinfection should be done. The letter was developed in collaboration with the National Institutes on Drug Abuse (NIDA) of the National Institute of Health (NIH) and the Center for Substance Abuse Treatment (CSAT) of the Substance Abuse and Mental Health Services Administration.


On February 9-10, 1993, the Centers for Disease Control and Prevention (CDC), CSAT, and NIDA cosponsored a workshop at Johns Hopkins University, Baltimore, Maryland. The workshop reviewed current practices and research on the use of bleach to disinfect drug injection equipment.

Several papers in the 1980s showed that bleach inactivated HIV in vitro (MMWR 1982; 31:577-80, Lancet 1984; 2:899-900, J Infect Dis 1985; 152:400-3, and JAMA 1986; 255:1887-91). Those studies reported the effectiveness of bleach in inactivating HIV as 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 IDUs by outreach workers throughout the country, providing an important contact with out-of-treatment drug users. Distribution of bleach is an important element of outreach to IDUs; that outreach provides IDUs with AIDS prevention education and recruitment into drug abuse treatment.

Recent Research on Bleach

Recent data raising questions about the efficacy of bleach cleaning were discussed at the Baltimore workshop. Bleach was found to be more effective than most other readily available solutions, such as alcohol and hydrogen peroxide, but bleach was not as effective against HIV in blood as it was against cell-free HIV and HIV in cell culture (N. Flynn et al., Sixth International Conference on AIDS, 1990 Abstract, S.C.761;3:279). Studies of the HIV seroconversion rates among a cohort of IDUs in Baltimore compared those who reported using disinfectants all the time with those who reported never using disinfectants to clean needles and syringes. No significant difference of seroconversion was found between disinfectant users and non-users (D.Vlahov et al., Epidemiology 1991;2:444-6, and unpublished data). A NIDA study found that a 10 percent dilution of household bleach (0.5 percent sodium hypochlorite) was not effective in removing blood from syringes using a 6-second rinse with bleach, followed by two 6-second rinses with water. Clotted blood was more difficult to clean from syringes than fresh blood (C. Contoreggi et al., Eighth international Conference on AIDS, 1992, Abstract P.C. 4280;2:291). Bleach may initially enhance clot formation when mixed with blood, which may hinder HIV inactivation (C. Contoreggi, unpublished data). Full-strength household bleach (5.25 percent sodium hypochlorite) effectively inactivated pelleted HIV at exposures of 30 seconds or greater, whereas 10 percent bleach was effective only after exposures of 2 hours (P. Shapshak et al., J AIDS 1993;6:218-9[letter]). A study of videotapes of drug users re-enacting the last time they injected drugs found that of those who used bleach, 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 (A. Gleghorn, unpublished data).

Implications of These Findings

These research findings indicate that we must strengthen our efforts to help IDUs stop using and injecting drugs. Treatment for drug use (e.g., methadone treatment for opiate use) is very important in helping drug users stop or decrease drug use and drug injection. Those who continue to inject drugs must be encouraged to always use sterile injection equipment and warned to never re-use or share needles, syringes, and other injection equipment. Disinfecting previously used needles and syringes with bleach (or other chemicals) can reduce the risk of HIV transmission but is not as safe as always using a sterile needle and syringe. Care should be taken also not to re-use or share cotton balls, cookers, rise/wash water, and other drug preparation and injection equipment because they may be contaminated with blood.

Drug users who continue to re-use or share injection equipment should be aware that this practice carries a high risk for acquiring and transmitting HIV. Injection equipment is not made to be re-used. Boiling needles and syringes for 15 minutes is one way to sterilize equipment between uses. However, boiling may alter the shape and utility of the widely used plastic needles and 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 shared.

Provisional Recommendations

There is currently insufficient laboratory and behavioral research to make definitive recommendations on the best procedures for bleach disinfection. However, we believe the following steps will enhance the effectiveness of bleach disinfection on needles and syringes:

  • Cleaning should be done twice—once immediately after use and again just before re-use of needles and syringes.
  • Before using bleach, wash out the needle and syringe by filling them several times with clean water. (This will reduce the amount of blood and other debris in the syringe. Blood reduces the effectiveness of bleach).
  • Then, use full-strength liquid household bleach (not diluted bleach).
  • Completely fill the needle and syringe with bleach several times. (Some suggest filling the syringe at least 3 times).
  • The longer the syringe is completely full of bleach, the more likely HIV will be inactivated. (Some suggest the syringe should be full of bleach for at least 30 seconds).
  • After using bleach, rinse the syringe and needle by filling several times with clean water. Don’t re-use water used for initial pre-bleach washing; it may be contaminated.
  • For every filling of the needle and syringe with pre-bleach wash water, bleach, and rinse water, fill the syringe completely (“to the top”).
  • Shaking and tapping the syringe are recommended when the syringe is filled with pre-bleach wash water, bleach, and rinse water. Shaking the syringe should improve the effectiveness of all steps.
  • Taking the syringe apart (removing the plunger) may improve the cleaning/disinfection of parts (e.g., behind the plunger) might not be reached by solutions in the syringe.

Staff of HIV prevention programs should review how the use of bleach is currently taught and promoted and how IDUs are using bleach. The principles of bleach disinfection described in this letter should be incorporated into guidance provided to IDUs. HIV prevention program staff, outreach staff, and drug users should work together to develop easily understood messages to communicate these steps.


Bleach disinfection of needles and syringes continues to have an important role in reducing the risk of HIV transmission for IDUs who have no other option but to re-use or share a needle and syringe. The use of full-strength bleach as described should improve the effectiveness of the bleach disinfection.

Availability of Needles and Syringes

Given the importance of IDU access to sterile needles and syringes, public health officials may wish to review local laws and regulations that affect needle/syringe availability and possession (MMWR 1993; 42:145-8). IDUs’ access to sterile needles and syringes can be limited by state and Federal laws, including (1) prescription laws that require a physician’s prescription as a condition for pharmacy sale of needles and syringes (in 11 states and the District of Columbia), and (2) drug paraphernalia laws that place criminal penalties on the possession and distribution of needles and syringes (in approximately 44 states and the District of Columbia). At this time, certain Federal statutes such as, for example, the Substance Abuse Prevention and Treatment block Grant, 42 U.S.C. § 300x-31, and the Ryan White Comprehensive AIDS Resources Emergency Act, 42 U.S.C. § 300ff-1, have prohibitions on using funds obtained under those programs to distribute needles or syringes for illegal drug use. Needle/syringe exchange (NSE) programs may provide additional means of increasing the availability of sterile needles and syringes to decrease the re-use of injection equipment by addicts; however, the risks and benefits of NSE programs are still under study.


CDC, CSAT, and NIDA continue to collaborate in developing policy recommendations in this area, and in additional laboratory, epidemiologic, and behavioral studies.

Contact Numbers

For additional information or to comment, please contact the following persons:

CDC – Dr. James W. Curran at 404-639-0900 or Dr. T. Stephen Jones at;

CSAT – Warren Hewitt or Adolfo Mata at 301-443-8160; and

NIDA – Richard A. Millstein at 301-443-6480 or Dr. Harry Haverkos at 301-443-6697.

Sincerely yours,

James W. Curran, M.D., M.P.H.
Assistant Surgeon General
Associate Director for HIV/AIDS
Centers for Disease Control and Prevention

Lisa W. Scheckel, M.P.M.
Acting Director
Center for Substance Abuse Treatment

Richard A. Millstein
Acting Director
National Institute on Drug Abuse

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