Survival of Hepatitis C Virus in Syringes Is Dependent on the Design of the Syringe- Needle and Dead Space Volume

There is now widespread recognition that syringes with detachable needles can increase the transmission of HIV and viral hepatitis among people who inject drugs in comparison to syringes with fixed needles. This is due to the larger ‘dead space’ where the detachable needle meets the syringe. Recently, there have been at least two attempts to manufacture detachable needle and syringe combinations with decreased dead space.

We have developed a laboratory assay that allows us to quantify recovery of hepatitis C virus (HCV) from the small volumes remaining within syringes. We used this assay to compare the recovery of infectious HCV from standard detachable syringe-needle combinations, reduced dead space combinations, and syringes fixed needles.

In summary, the recovery of HCV was lowest from the syringes with fixed needles and only marginally better in the reduced dead space combinations compared to standard detachable combinations. We also observed that although a single rinse with water could reduce HCV to below the level of detection in fixed needle syringes, multiple rinses with water were needed to eliminate detectable HCV from all types of detachable combinations.

We therefore recommend:
(1) that people who inject drug use only syringes with fixed needles unless they have no alternative, and
(2) if they have no alternative, they rinse all previously used needles and syringes at least three times with water before using them again.

We are presently running similar experiments with HIV recovery from these syringes and needles and will report that information once the data analysis is complete.

Read the full study here

Robert Heimer

Yale School of Public Health