It remains uncertain whether hepatitis C virus (HCV) incidence linked to sharing injection paraphernalia among people who inject drugs (PWID) reflects contamination of the paraphernalia or syringe-mediated contamination when drugs are shared. For a study published in The Journal of Infectious Diseases, Robert Heimer, PhD, and colleagues sought to determine whether transmission of the virus was due to the process of preparing drugs, rather than the objects used.

The researchers replicated the process of preparing drugs for a shared injection using HCV-contaminated input syringes. Water drawn into input syringes was transferred to a cooker and drawn through a cotton filter into receptive syringes to determine which objects retained HCV. “We simulated the process with two commonly used syringes and compared the recovery of infectious hepatitis C from the four objects,” explains Dr. Heimer. Recovery of infectious HCV was measured following 3 days propagation of virus in a permissive tissue culture system.

The study team found that recovery rates from receptive syringes were higher when comparing detachable needles with fixed needles (93.8% vs 45.7%) as well as from the residue in input syringes following transfer of water to cookers (73.8% vs 0%) and receptive syringes. Rates of recovery from filters were low, but higher when the input syringes had detachable needles (15.4% vs 1.4% for input syringes with fixed needles). HCV could not be recovered from cookers regardless of input syringe type or cooker design. Dr. Heimer and colleagues concluded that the epidemiological association of sharing cookers and filters with incident HCV infections was a consequence of injecting with contaminated receptive syringes and less likely the result of reuse of the cookers or filters.

“There is no reason why physicians should not be able to prescribe syringes for injection drug users as an HCV prevention technique, if the patient is as-of-yet unwilling to change their lifestyle,” says Dr. Heimer. “Part of the physician’s role in preventing the spread of hepatitis C should be training safe injection techniques.”