Assessment of environmental viral contamination of liquids prepared in a closed system drug transfer device

Abstract

Background: Closed system transfer devices (CSTDs) enable preparation and transfer of drugs into syringes and infusion bags, while protecting healthcare professionals from exposure to hazardous drugs. Drug products contaminated by bacteria or viruses harbor a clinical risk to patients. Therefore, CSTDs must also prevent environmental contamination of the compounded liquid. Some CSTDs require priming of syringes with environmental air and introduction of this air into the drug vial for pressure equalization during liquid withdrawal. We examined whether this methodology puts the vial contents at risk for contamination by the human coronavirus OC43 (HCoV-OC43). Methods: A CSTD requiring syringe priming was used to transfer liquids between a sterile vial containing saline, a sterile syringe, and, in some cases, an intravenous (IV) bag inside a sealed glove box contaminated by HCoV-OC43 aerosols. Viral contamination of the transferred liquids after a single transfer into a syringe, or after 3 transfers (from the vial into the syringe then from the syringe into the IV bag, and from the IV bag back into the syringe), was assessed by detecting the presence of HCoV-OC43 RNA using quantitative real-time polymerase chain reaction. Results: Liquid transferred in a sterile environment using the CSTD was not contaminated but liquid transferred once from the vial into a syringe in a coronavirus-contaminated environment showed cycle threshold (Ct) values corresponding to 3.8-9.4 plaque forming units (PFU)/ml in all 9 replicates tested. Liquid transferred three times in a coronavirus-contaminated environment showed Ct values corresponding to 2.5-4 PFU/ml, but in 3 of the 9 replicates tested Ct values were not detected. Conclusions: Liquids contained by CSTDs are susceptible to HCoV-OC43 contamination when the CSTD used requires aspiration of environmental air into a syringe.