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. 2020 Nov;106(3):577-584.
doi: 10.1016/j.jhin.2020.08.025. Epub 2020 Sep 1.

The use of germicidal ultraviolet light, vaporized hydrogen peroxide and dry heat to decontaminate face masks and filtering respirators contaminated with a SARS-CoV-2 surrogate virus

L F Ludwig-Begall  1 , C Wielick  1 , L Dams  1 , H Nauwynck  2 , P-F Demeuldre  3 , A Napp  3 , J Laperre  4 , E Haubruge  5 , E Thiry  6
Affiliations

The use of germicidal ultraviolet light, vaporized hydrogen peroxide and dry heat to decontaminate face masks and filtering respirators contaminated with a SARS-CoV-2 surrogate virus

L F Ludwig-Begall et al. J Hosp Infect. 2020 Nov.

Abstract

Background: In the context of the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, the supply of personal protective equipment remains under severe strain. To address this issue, re-use of surgical face masks and filtering facepiece respirators has been recommended; prior decontamination is paramount to their re-use.

Aim: We aim to provide information on the effects of three decontamination procedures on porcine respiratory coronavirus (PRCV)-contaminated masks and respirators, presenting a stable model for infectious coronavirus decontamination of these typically single-use-only products.

Methods: Surgical masks and filtering facepiece respirator coupons and straps were inoculated with infectious PRCV and submitted to three decontamination treatments, ultraviolet (UV) irradiation, vaporized H2O2, and dry heat treatment. Viruses were recovered from sample materials and viral titres were measured in swine testicle cells.

Findings: UV irradiation, vaporized H2O2 and dry heat reduced infectious PRCV by more than three orders of magnitude on mask and respirator coupons and rendered it undetectable in all decontamination assays.

Conclusion: This is the first description of stable disinfection of face masks and filtering facepiece respirators contaminated with an infectious SARS-CoV-2 surrogate using UV irradiation, vaporized H2O2 and dry heat treatment. The three methods permit demonstration of a loss of infectivity by more than three orders of magnitude of an infectious coronavirus in line with the United States Food and Drug Administration policy regarding face masks and respirators. It presents advantages of uncomplicated manipulation and utilization in a BSL2 facility, therefore being easily adaptable to other respirator and mask types.

Keywords: Decontamination (UV, H(2)O(2), dry heat); PRCV; Respirator; SARS-CoV-2; Surgical mask.

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Figures

Figure 1
Figure 1
Recovery of virus after elution from inoculated, untreated surgical masks and filtering facepiece respirators (FFRs). Recovery of infectious porcine respiratory coronavirus from inoculated untreated surgical masks (SM) and FFRs was analysed in swine testicular cells. The cell culture limit of detection (LOD) was 0.8 log10 TCID50/mL (6.31 × 100). Similar levels of virus recovery were detected for left, right and middle (L, R, M) coupons of masks and respirators; recovery efficacy of infectious virus from straps (S) deviated significantly in all analyses from the mean of all coupons and remained below the LOD for all assays performed on FFR straps. P-values were computed using a two-sided independent sample t-test to calculate differences between individual coupon values and differences between mean values of all coupons and straps, where ∗∗∗∗P<0.0001, ∗∗∗P<0.001, ∗∗P<0.01, ∗P<0.05, and ns is P≥0.05. UV, ultraviolet.
Figure 2
Figure 2
Effect of three decontaminating treatments on porcine respiratory coronavirus (PRCV)-inoculated surgical mask- and filtering facepiece respirator (FFR) coupons and straps PRCV recovered from surgical masks (SM) and FFRs decontaminated via exposure to ultraviolet light (UV), vaporized hydrogen peroxide (H2O2), or dry heat treatment was analysed in swine testicular cells. The cell culture limit of detection (LOD) was 0.8 log10 TCID50/mL for all analyses except those concerning H2O2-treated SM or FFR straps (1.8 log10 TCID50/mL). Per decontamination method, nine PRCV-inoculated, decontaminated coupons (N = 9) and three inoculated, decontaminated straps (N = 3) were analysed in parallel to inoculated, untreated, positive control coupons (N = 9) and straps (N = 3). Sample size deviated for UV-decontaminated FFR respirators, where N = 6 coupons (left and right) were analysed. P-values were computed using a two-sided independent sample t-test, where ∗∗∗∗P<0.0001, ∗∗∗P<0.001, ∗∗P<0.01, ∗P<0.05, and ns is P≥0.05.
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References

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