The effect of ultraviolet C radiation against different N95 respirators inoculated with SARS-CoV-2

Int J Infect Dis. 2020 Nov;100:224-229. doi: 10.1016/j.ijid.2020.08.077. Epub 2020 Sep 3.

Abstract

Objectives: There are currently no studies that have examined whether one dosage can be uniformly applied to different respirator types to effectively decontaminate SARS-CoV-2 on N95 filtering facepiece respirators (FFRs). Health care workers have been using this disinfection method during the pandemic. Our objective was to determine the effect of UVC on SARS-CoV-2 inoculated N95 respirators and whether this was respirator material/model type dependent.

Methods: Four different locations (facepiece and strap) on five different N95 FFR models (3M 1860, 8210, 8511, 9211; Moldex 1511) were inoculated with a 10 μL drop of SARS-CoV-2 viral stock (8 × 107 TCID50/mL). The outside-facing and wearer-facing surfaces of the respirators were each irradiated with a dose of 1.5 J/cm2 UVC (254 nm). Viable SARS-CoV-2 was quantified by a median tissue culture infectious dose assay (TCID50).

Results: UVC delivered using a dose of 1.5 J/cm2, to each side, was an effective method of decontamination for the facepieces of 3M 1860 and Moldex 1511, and for the straps of 3M 8210 and the Moldex 1511.

Conclusion: This dose is an appropriate decontamination method to facilitate the reuse of respirators for healthcare personnel when applied to specific models/materials. Also, some straps may require additional disinfection to maximize the safety of frontline workers. Implementation of widespread UVC decontamination methods requires careful consideration of model, material type, design, and fit-testing following irradiation.

Keywords: COVID-19; Healthcare personnel; N95; Reuse; SARS-Co-V2; Ultraviolet C.

Publication types

  • Evaluation Study

MeSH terms

  • Decontamination / methods*
  • Disinfection / methods
  • Dose-Response Relationship, Radiation
  • Equipment Reuse
  • Humans
  • Masks / virology*
  • Pandemics
  • SARS-CoV-2 / physiology*
  • SARS-CoV-2 / radiation effects*
  • Ultraviolet Rays*
  • Ventilators, Mechanical / virology*