“Don, doff, discard” to “don, doff, decontaminate”—FFR and mask integrity and inactivation of a SARS-CoV-2 surrogate and a norovirus following multiple vaporised hydrogen peroxide-, ultraviolet germicidal irradiation-, and dry heat decontaminations

Abstract

Background As the SARS-CoV-2 pandemic accelerates, the supply of personal protective equipment remains under strain. To combat shortages, re-use of surgical masks and filtering facepiece respirators has been recommended. Prior decontamination is paramount to the re-use of these typically single-use only items and, without compromising their integrity, must guarantee inactivation of SARS-CoV-2 and other contaminating pathogens. Aim We provide information on the effect of time-dependent passive decontamination (infectivity loss over time during room temperature storage in a breathable bag) and evaluate inactivation of a SARS-CoV-2 surrogate and a non-enveloped model virus as well as mask and respirator integrity following active multiple-cycle vaporised hydrogen peroxide (VHP), ultraviolet germicidal irradiation (UVGI), and dry heat (DH) decontamination. Methods Masks and respirators, inoculated with infectious porcine respiratory coronavirus or murine norovirus, were submitted to passive decontamination or single or multiple active decontamination cycles; viruses were recovered from sample materials and viral titres were measured via TCID50 assay. In parallel, filtration efficiency tests and breathability tests were performed according to EN standard 14683 and NIOSH regulations. Results and discussion Infectious porcine respiratory coronavirus and murine norovirus remained detectable on masks and respirators up to five and seven days of passive decontamination. Single and multiple cycles of VHP-, UVGI-, and DH were shown to not adversely affect bacterial filtration efficiency of masks. Single- and multiple UVGI did not adversely affect respirator filtration efficiency, while VHP and DH induced a decrease in filtration efficiency after one or three decontamination cycles. Multiple cycles of VHP-, UVGI-, and DH slightly decreased airflow resistance of masks but did not adversely affect respirator breathability. VHP and UVGI efficiently inactivated both viruses after five, DH after three, decontamination cycles, permitting demonstration of a loss of infectivity by more than three orders of magnitude. This multi-disciplinal approach provides important information on how often a given PPE item may be safely reused.

Noroviruses—The State of the Art, Nearly Fifty Years after Their Initial Discovery

“…Highly tenacious and resistant in the face of various virucidal treatments and decontamination methods [ 195 , 196 , 197 ], HuNoVs are transmitted either via direct person-to-person contact or by consumption of contaminated water or food ( Figure 4 ) [ 198 ]. Infectious viruses can enter environmental waters either via direct discharge or release of improperly treated sewage from industrial-scale or small private wastewater treatment plants, discharges from vessels, as well as urban runoff, the latter especially in times of flooding or heavy rainfall which have been linked to a high prevalence of HuNoVs in coastal waters [ 199 , 200 , 201 , 202 ].…”

“…Norovirus outbreaks are often reported in the context of communal dining at restaurants, festivals, picnics, schools, cruise ships and military bases [ 216 , 217 , 218 , 219 ] or in institutional settings such as hospitals and care homes, where spread of infection from a common-source exposure is facilitated by enclosed living quarters and reduced personal hygiene [ 146 , 220 , 221 , 222 ]. In the context of PPE donning and doffing (this particularly in the context of the ongoing coronavirus pandemic), contamination of healthcare personnel, but particularly untrained users, with tenacious oral or respiratory pathogens that may contaminate masks or respirators has become a concern [ 196 , 197 ].…”

“…Norovirus outbreaks are often reported in the context of communal dining at restaurants, festivals, picnics, schools, cruise ships and military bases [216][217][218][219] or in institutional settings such as hospitals and care homes, where spread of infection from a common-source exposure is facilitated by enclosed living quarters and reduced personal hygiene [146,[220][221][222]. In the context of PPE donning and doffing (this particularly in the context of the ongoing coronavirus pandemic), contamination of healthcare personnel, but particularly untrained users, with tenacious oral or respiratory pathogens that may contaminate masks or respirators has become a concern [196,197]. Recently, wild birds and rodents were named as new potential HuNoV transmission routes; GI and GII HuNoV genome copies were detected in faecal samples of gulls and crows (31%) and rats (2%), albeit with high ct values, implicating them as possible mechanical carriers, capable of spreading HuNoVs in the environment and possibly transmitting the virus to humans directly or indirectly by contaminating foods [223].…”

Effect of five decontamination methods on face masks and filtering facepiece respirators contaminated with Staphylococcus aureus and Pseudomonas aeruginosa

“…This study, carried out in parallel with the previous ones [23][24][25], made it possible to evaluate the efficiency of five decontamination methods (UV decontamination, VHP, methylene blue treatment, dry heat treatment and ethanol treatment) on two opportunistic bacteria, one Gram-positive strain, S. aureus ATCC 29213, and one Gram-negative strain, P. aeruginosa S0599, commonly present in the medical environment.…”

“…To validate these five decontamination methods for SARS-CoV-2 on SMs and FFRs, a study was carried out in parallel for the same project at the University of Liege with porcine respiratory coronavirus with a dry heat method, UV method and vaporized H 2 O 2 (VHP) [ 23 ] and methylene blue photodynamic treatment [ 24 ]. Another study was carried out in parallel using the same protocols of decontamination and using filtration efficiency tests and breathability tests after reusing the mask [ 25 ].…”