Bleaching of Syringes May Help to Reduce Risk of Hepatitis C among Injection Drug Users

NEW YORK CITY, Nov. 11 - Injection drug users who consistently disinfect their needles with household-strength bleach between injections appear to reduce their risk of hepatitis C infection, according to a preliminary study in the November issue of the journal Epidemiology. The study's two lead authors are researchers at The New York Academy of Medicine.

Hepatitis C virus has emerged as a major health problem among injection drug users (IDUs). While stopping drug use or using new, sterile syringes each time are established methods of reducing hepatitis C transmission, the population at greatest risk - new, younger injectors - is often unable or not ready to stop drug use. In addition, availability of sterile syringes is often limited.

Since bleach is inexpensive, readily available and easy to use, it may prove to be an additional preventative measure against hepatitis C transmission, said lead author Farzana Kapadia, a Project Director in the Center for Urban Epidemiologic Studies at the Academy. The results of this study, entitled "Does Bleach Disinfection of Syringes Protect Against Hepatitis C Infection among Young Adult Injection Drug Users?" are not conclusive but are intriguing enough to warrant further investigation, she said.

"Bleach disinfection of syringes, while not a substitute for use of sterile needles or cessation of injection, may help to prevent hepatitis C infection among injection drug users," Kapadia said. The two proven ways to reduce disease transmission -- stopping drug use, and using new sterile syringes for every injection -- may not be options for everyone.

Researchers examined data from the multi-site Collaborative Injection Drug Users Study, a CDC funded study, which recruited IDUs from five U.S. cities between 1997 and 1999. All participants were between 18 and 30 years old and were at heightened risk for hepatitis C infection, because they shared syringes or other paraphernalia with fellow drug users. Shared paraphernalia may include: drug cookers, which are used to melt drugs into a liquid; cottons, which are used to filter out particles as drugs are drawn into a syringe; or rinse water.

As part of this study, participants had received hepatitis C testing and were interviewed about risk behaviors and steps they had taken to prevent infection. Scientists from the Academy and their colleagues used that data to compare 78 IDUs who had become infected with hepatitis C during the two-year study with 390 IDUs who had not. Kapadia and colleagues analyzed whether bleach disinfection of syringes played a protective role and in fact, found that it might. Odds of becoming infected with hepatitis C were 65% lower among IDUs who reported using bleach "all the time" and were 24% lower among IDUs reporting bleach use "less than all the time".

David Vlahov, a co-author of the study and director of the Academy's Center for Urban Epidemiologic Studies, showed in 1991 that HIV transmission was not effectively blocked by IDUs who disinfect their needles with bleach. That study, also published in Epidemiology, may have left people with the belief that bleach disinfection never effectively stops viral transmission, which is not necessarily the case, Vlahov said. The reason bleach disinfection did not work completely for blocking HIV transmission was not due to the bleach itself but rather how well and often the drug users bleached the needles. The difference in results between the studies may reflect that there is more hepatitis C virus than HIV in the blood and therefore, even imperfect bleaching of the needles may have some impact on reducing the amount of hepatitis C left in syringes. Another possibility is that bleaching practices have improved in injection drug user populations since 1991.

"While bleach may not be completely effective for HIV, it may still be worthwhile to re-examine bleach disinfection if it can help for hepatitis C," Vlahov said. "It is clearly not a complete or long term solution to the problem by itself, but until we have an effective vaccine, different strategies need to be developed and evaluated."

To read the abstract of this study, visit www.epidem.com, click on "Contents" and select "November 2002."

The New York Academy of Medicine is a non-profit institution founded in 1847 that is dedicated to enhancing the health of the public through research, education and advocacy, with a particular focus on urban populations, especially the disadvantaged.

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Posted on November 11, 2002

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