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Reusability of filtering facepiece respirators after decontamination through drying and germicidal UV irradiation
  1. David Vernez1,
  2. Jonathan Save2,
  3. Anne Oppliger1,
  4. Nicolas Concha-Lozano3,
  5. Nancy B Hopf1,
  6. Hélène Niculita-Hirzel1,
  7. Grégory Resch2,
  8. Véronique Michaud4,
  9. Laurie Dorange-Pattoret1,
  10. Nicole Charrière1,
  11. Kiattisak Batsungnoen1,5,
  12. Guillaume Suarez1
  1. 1Unisanté, Department of Occupational and Environmental Health, University of Lausanne, Lausanne, Switzerland
  2. 2Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
  3. 3Unit of Forensic Toxicology and Chemistry, CURML, University of Lausanne, Lausanne, Switzerland
  4. 4Laboratory for Processing of Advanced Composites (LPAC), Institute of Materials (IMX), Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
  5. 5Institute of Public Health, Suranaree University of Technology, Nakhon Ratchasima, Thailand
  1. Correspondence to Professor David Vernez; david.vernez{at}


Introduction During pandemics, such as the SARS-CoV-2, filtering facepiece respirators plays an essential role in protecting healthcare personnel. The recycling of respirators is possible in case of critical shortage, but it raises the question of the effectiveness of decontamination as well as the performance of the reused respirators.

Method Disposable respirators were subjected to ultraviolet germicidal irradiation (UVGI) treatment at single or successive doses of 60 mJ/cm2 after a short drying cycle (30 min, 70°C). The germicidal efficacy of this treatment was tested by spiking respirators with two staphylococcal bacteriophages (vB_HSa_2002 and P66 phages). The respirator performance was investigated by the following parameters: particle penetration (NaCl aerosol, 10–300 nm), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry and mechanical tensile tests.

Results No viable phage particles were recovered from any of the respirators after decontamination (log reduction in virus titre >3), and no reduction in chemical or physical properties (SEM, particle penetrations <5%–6%) were observed. Increasing the UVGI dose 10-fold led to chemical alterations of the respirator filtration media (FTIR) but did not affect the physical properties (particle penetration), which was unaltered even at 3000 mJ/cm2 (50 cycles). When respirators had been used by healthcare workers and undergone decontamination, they had particle penetration significantly greater than never donned respirators.

Conclusion This decontamination procedure is an attractive method for respirators in case of shortages during a SARS pandemic. A successful implementation requires a careful design and particle penetration performance control tests over the successive reuse cycles.

  • prevention strategies
  • public health
  • SARS

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  • Handling editor Seye Abimbola

  • Contributors DV, GS, AO, NBH, HN-H, NC-L and KB, conceived and designed the study. GS, JS, AO, NC-L, GR, VM, LD-P and NC acquired the data. DV, GS, AO, HN-H, GR and VM contributed to data interpretation and analysis. DV, GR, VM and GS wrote the first draft of the manuscript, and all authors were involved in critical revision of the article and approved the final version for publication.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Experimental data are available on request from the corresponding author (

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.

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