Hepatitis C Virus Contamination of Vial Surfaces

Anesthesiology, May 2019.

A 2014 hepatitis C outbreak at several Ontario (Canada) colonoscopy clinics led to significant study that targeted contaminated medication practices by anesthesia providers. Follow-up investigations revealed just how easily the hepatitis C virus (HCV) is transferred from previously sterile needles and syringes into medication vials, if the diaphragm has been previously contaminated. Common vial cleaning practices were found not to be sufficient to prevent HCV transmission.

A substantial body of research clearly demonstrates that we routinely contaminate our anesthesia workstations with practices that have previously not been carefully scrutinized. Certainly, the way we draw up drugs and administer them to patients is plagued by opportunities for contamination.

The investigators were concerned that during the care of an HCV-infected patient providers might contaminate the diaphragm of the medication vials that are subsequently used. They undertook a sequential set of studies beginning with a simulated contamination of multidose medication vials that contained cell culture media. Then they sought to determine whether HCV remains viable over time in commonly used medications in sufficient quantities to initiate an infection using similar infection protocols on the outside of the vials. Lastly, they examined the effect of common cleaning practices on the eradication of HCV infectivity.

Problems with infectivity and viral durability were found in all the tests. For example, a single wipe of the diaphragm with 70% isopropyl alcohol was not able to eliminate HCV infectivity; a 10-second wipe dramatically reduced the risk for contamination but did not completely eliminate HCV infectivity.

Education is key, as is perhaps a change in practice, which is being discussed nationwide.  Maybe our “one vial for one patient” routine is insufficient to eliminate risk of viral and bacterial transmission. Perhaps it is an issue of need for greater vigilance. Some suggest that our patients would be better off if those medications were prepared under sterile conditions in the pharmacy. But that involves the risk of significant logistics, waste, and of course money. Stay tuned for future developments.