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Risk aspects of used works
Robert Heimer, Professor, Department of Epidemiology and Public Health, Yale University School of Medicine, Connecticut, USA

Abstract
Analysis of the impact of syringe distribution and exchange schemes has clearly demonstrated that the removal of contaminated syringes from circulation is a key element in reducing the transmission of blood borne viruses. Prolonged survival of HIV, hepatitis B virus (HBV), and hepatitis C (HCV) virus for periods of weeks inside the barrel of used syringes makes sharing of used syringes dangerous, but there are times when a clean syringe is not accessible. Fortunately, steps can be taken to reduce the potential for virus transmission. Rinsing syringes with water, then chlorine bleach, then water again will virtually eliminate HIV and HCV and is likely to have the same effect on HBV. Less effective, but still somewhat protective is three washes with clean water, which will reduce the risk of a syringe containing enough HIV to transmit an infection by more than 95%.

Because of the higher numbers of HBV and HCV particles in blood relative to HIV, three rinses with water are unlikely to same impact in reducing the risk of transmitting the hepatitis viruses. While used syringes pose a significant threat to those who reuse them for injection, syringes in the litter stream pose a much lower risk for transmitting HIV or HCV when encountered via a needlestick. This is because the needlestick generally involves no contact with fresh blood or the internal contents of the syringe, but only with dried blood on the outside of the needle. HIV and HCV are rapidly inactivated by drying. However, needlesticks can still transmit HBV, a virus that remains viable even when dry.

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Biography
Dr. Heimer's major research efforts include scientific investigation of the mortality and morbidity associated with injection drug use. Areas of investigation include syringe exchange programs, virus survival in syringes, hepatitis B vaccination, hepatitis C transmission risks, overdose prevention and resuscitation, and pharmacological treatment of opiate addiction. His research combines laboratory, operational, behavioral, and structural analyses to evaluate the effectiveness of intervention programs in preventing the negative medical consequences of injection drug use.

Dr. Heimer is Director of the Interdisciplinary Research Methods Core at Yale's Center for Interdisciplinary Research on AIDS (CIRA). His current work focuses on he contexts and consequences of drug abuse and attempts to provide health and prevention practitioners with information needed to assist their educational and advocacy efforts.