Survival of Hep C in syringes may explain high transmission amongst IVDUs

An article in JID published by Paintsil et al. 2010 hypothesized that the efficient transmission of HCV among IDUs may be partly due to the ability of the virus to remain viable in contaminated syringes for prolonged periods. (It is estimated that the probability of transmission of HCV per exposure to a contaminated syringe is 5‐fold to 20‐fold higher than that of HIV transmission).  

To test this hypothesis, they developed a microculture assay that allowed us to propagate HCV from small residual volumes contained in the dead space of syringes used by IDUs, and to determine the effects of storage at different temperatures for prolonged periods on the viability of HCV in syringes.

The authors found out that Insulin syringes failed to yield viable HCV beyond day 1 at all storage temperatures except 4°, in which 5% of syringes yielded viable virus on day 7; Tuberculin syringes yielded viable virus from 96%, 71%, and 52% of syringes after storage at 4°, 22°, and 37° for 7 days, respectively, and yielded viable virus up to day 63. 

Conclusions.The high prevalence of HCV among injection drug users may be partly due to the prolonged survival of viruses in syringes and the syringe type. . Our findings may be used to guide prevention strategies.

Further studies are also needed to determine whether higher HCV transmission amongst IVDU are due to differences in viral infectivity / inoculum size required to cause infection.  

http://www.journals.uchicago.edu/doi/full/10.1086/656212