Evaluation of UV-C Radiation Efficiency in the Decontamination of Inanimate Surfaces and Personal Protective Equipment Contaminated with Phage ϕ6

Abstract

To help halt the global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), appropriate disinfection techniques are required. Over the last years, the interest in Ultraviolet-C (UV-C) radiation as a method to disinfect inanimate surfaces and personal protective equipment (PPE) has increased, mainly to efficiently disinfect and prevent SARS-CoV-2 from spreading and allow for the safe reuse of said equipment. The bacteriophage ϕ6 (or simply phage ϕ6) is an RNA virus with a phospholipid envelope and is commonly used in environmental studies as a surrogate for human RNA-enveloped viruses, including SARS-CoV-2. The present study investigated the use of two new UV irradiation systems ((2)2.4W and (8)5.5W)) constituted by conventional mercury UV-C lamps with a strong emission peak at ~254 nm to potentially inactivate phage ϕ6 on different surfaces (glass, plastic, stainless steel, and wood) and personal protective equipment, PPE, (surgical and filtering facepiece 2, FFP2, masks, a clear acetate visor, and disposable protective clothing). The results showed that both UV-C systems were effective in inactivating phage ϕ6, but the UV-C sterilizing chamber (8)5.5W had the best disinfection performance on the tested surfaces. The inactivation effectiveness is material-dependent on all surfaces, reaching the detection limit of the method at different times (between 60 and 240 s of irradiation). The glass surface needed less time to reduce the virus (30 s) when compared with plastic, stainless, and wood surfaces (60 s). The virus inactivation was more effective in the disposable surgical and FFP2 masks (60 and 120 s, respectively) than in the disposable vest and clear acetate visor (240 s). Overall, this study suggests that UV-C lamps with peak emission at ~254 nm could provide rapid, efficient, and sustainable sanitization procedures to different materials and surfaces. However, dosage and irradiation time are important parameters to be considered during their implementation as a tool in the fight against human coronaviruses, namely against SARS-CoV-2.

Rapid SARS-CoV-2 disinfection on distant surfaces with UV-C: The inactivation is affected by the type of material

“…However, in the absence of UV-C radiation a lower amount of viable virus could be recovered from these two materials (23.6% and 27.2% of the amount of virus recovered from polystyrene plates for steel and varnished MDF, respectively, Table 1 ). In studies performed with phage ϕ6, as a surrogate for SARS-CoV-2, virus inactivation on white-melamine faced chipboard sheets (similar to varnished wood) was also similar to that observed for stainless steel [25] . Furthermore, and in agreement with our results, SARS-CoV-2 deposited on plastic and steel surfaces had a titer reduction of approximately 2-3 logs after irradiation with an UV-C dose of 10.25 mJ/cm 2 very similar to ours [12] .…”

Virus Behavior after UV254 Treatment of Materials with Different Surface Properties

“…A 2022 study evaluated the efficacy of UV 254 inactivation on glass, plastic, wood, stainless steel, and PPE products [ 36 ]. The authors used Bacteriophage Phi 6 as the surrogate at concentrations of approximately 10 8 PFU/mL.…”

UV-A Radiation: Safe Human Exposure and Antibacterial Activity

“…The antimicrobial activity of UV radiation has been known for long time and is used in applications such as sterilization [1][2][3][4][5][6][7][8]. The efficiency of UV antimicrobial effects mostly depends on the wavelength range.…”