Table 3.

Properties of different decontamination approaches considered for PPE reprocessing and reuse.^a

	Hydrogen Peroxide Vapour (VH2O2)	Ethylene Oxide (EO)	Ultraviolet Germicidal Light	Moist Heat	Chemical Liquid Disinfectants	Gamma Irradiation
Methodology	Penetration of sterilant gas	Penetration of sterilant gas	Surface irradiation	Penetration by heat (such as 60 °C for 30 min delivers 4 log reduction)	Surface disinfection	Irradiation of product using photons from radioisotope
Efficacy of process	Process efficacy confirmed by biological indicators and/or process monitoring	Process efficacy confirmed by biological indicators and/or process monitoring	Variable, but process efficacy confirmed by biological indicators or monitoring UV dose	Process efficacy confirmed by biological indicators and/or process monitoring	Process efficacy confirmed by international standards on biocide testing	Process parameter confirmed using dosimetry
Penetration (such as use of packaging)	Limited penetration Requires gas permeable packaging and product design	Requires gas permeable packaging and product design	Not suitable for packaged PPE	Suitable for treatment of packaged PPE – but depends upon specific sensitivity of materials	Not applied or suitable for packaged PPE but could be used for surface disinfection	Good penetration complete even at high densities (>0.4 g/cc)
Material Compatibility	Good material compatibility but not with cellulose-based materials as degrades VH2O2	Very few material compatibility concerns	Broad material compatibility – longer exposures affects brittleness of PVC, straps of FFRs	Very broad compatibility	Variable depending upon biocide – but sodium hypochlorite or hydrogen peroxide (≤ 5% compatible with PPE	Compatible with most materials: plastics need to be evaluated. Avoid acetals, PTFE (Teflon), unstable polypropylene
Turnaround Time	All in one day processing	Days: conventional = 9–10 days. All-in-one processing = one day	Relatively short – typically ≤1 h but depends on UV dose	Relatively short, typically ≤1 h	Relatively short (generally ≤30 min)	Hours: time varies based on dose requirement
Process	Complex process that introduces VH2O2 under vacuum, treatment, aeration	Complex process: variables include time, temperature, humidity, and EO concentration	Simple rapid process: delivery of UV dose (J/cm2) in enclosed chamber	Simple rapid process – duration depends on combination of temp, RH and time	Simple rapid process – but affected by bioburden, pH, temperature	Simple process – variables include time in the cell and isotope load
Mechanisms of destruction	Potent oxidizer of proteins – but mechanism still not fully understood	Alkylation of proteins, enzymes (targeting sulfhydryl groups), DNA, and RNA.	Irreversible RNA damage affecting replication / infection in host	Thermal aggregation of SARS-CoV-2 nucleo-capsid and membrane proteins	Varied depending on biocide - targets cell envelope / capsid protein via coagulation	Physically breaks down viral RNA
Limitation	Not compatible with cellulose-based materials – complex process requiring monitoring and control	Concerns over residuals left on material that are toxic (carcinogenic and teratogenic)	Operator safety due to UV exposure – shading issues with filters of FFRs– need to turn item, but not with PUV	Limited by thermal-sensitivity of materials used in PPE	Certain disinfectants, sanitizers	Adversely affects material
Suitability for PPE Reuse	Yes –	No	Yes – but limited to eye protection	Yes	Yes – limited to Eye Protection; Starmed hood	No

^aHydrogen peroxide in vapour (VH2O2); Filtering facepiece respirators (FFRs); ethylene oxide (EO); Relative Humidity (RH). Adapted from McEvoy and Rowan (2019).