Evaluation of 2 Ultraviolet-C Light Boxes for Decontamination of N95 Respirators

Main Article Content

Jennifer L. Cadnum
Basya S. Pearlmutter
Daniel F. Li
Annette L. Jencson
Jacob G. Scott
Ian C. Charnas
Curtis Donskey

Abstract

Background:  Ultraviolet-C (UV-C) light devices are effective in reducing contamination on N95 filtering facepiece respirators.  However, limited information is available on whether UV-C devices meet the Food and Drug Administration’s (FDA) microbiological requirements for Emergency Use Authorization (EUA) for respirator bioburden reduction. 


Methods:  We tested the ability of 2 UV-C light boxes to achieve the 3-log10 microorganism reductions required for EUA for reuse by single users.  Whole 3M 1860 or Moldex 1513 respirators were inoculated on the exterior facepiece, interior facepiece, and internal fibers with bacteriophage MS2 and/or 4 strains of bacteria and treated with UV-C cycles of 1 or 20 minutes.  Colorimetric indicators were used to assess penetration of UV-C through the respirators.   


Results:  For 1 UV-C box, a 20-minute treatment achieved the required bioburden reduction for Moldex 1513 but not 3M 1860 respirators.  For the second UV-C box, a 1-minute treatment achieved the required bioburden reduction in 4 bacterial strains for the Moldex 1513 respirator.  Colorimetric indicators demonstrated penetration of UV-C through all layers of the Moldex 1513 respirator but not the 3M 1860 respirator. 


Conclusions:  Our findings demonstrate that UV-C box technologies can achieve bioburden reductions required by the FDA for EUA for single users but highlight the potential for variable efficacy for different types of respirators. 

Article Details

Section
Articles

References

CDC. Implementing filtering facepiece respirator (FFR) reuse, including reuse after decontamination, when there are known shortages of N95 respirators.: Centers for Disease Control Prevention; 2020 [updated August 4, 2020May 6, 2021]. Available from: https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html.

FDA. Decontamination System EUAs for Personal Protective Equipment: US Food and Drug Administration; 2021 [cited 2021 May 6, 2021]. Available from: https://www.fda.gov/medical-devices/coronavirus-disease-2019-covid-19-emergency-use-authorizations-medical-devices/decontamination-systems-personal-protective-equipment-euas.

Degesys NF, Wang RC, Kwan E, Fahimi J, Noble JA, Raven MC. Correlation Between N95 Extended Use and Reuse and Fit Failure in an Emergency Department. JAMA. 2020;324(1):94-6. doi: 10.1001/jama.2020.9843. PubMed PMID: 32496504; PMCID: PMC7273312.

Fabre V, Cosgrove SE, Hsu YJ, Jones GF, Helsel T, Bukowski J, Sobota M, Sick-Samuels AC, Milstone AM, Maragakis LL, Rock C, Centers for Disease C, Prevention Epicenters P. N95 filtering face piece respirators remain effective after extensive reuse during the coronavirus disease 2019 (COVID-19) pandemic. Infect Control Hosp Epidemiol. 2021:1-4. doi: 10.1017/ice.2021.76. PubMed PMID: 33602376; PMCID: PMC7971774.

Schumm MA, Hadaya JE, Mody N, Myers BA, Maggard-Gibbons M. Filtering Facepiece Respirator (N95 Respirator) Reprocessing: A Systematic Review. JAMA. 2021;325(13):1296-317. doi: 10.1001/jama.2021.2531. PubMed PMID: 33656543.

Cadnum JL, Li DF, Redmond SN, John AR, Pearlmutter B, Donskey CJ. Effectiveness of Ultraviolet-C Light and a High-Level Disinfection Cabinet for Decontamination of N95 Respirators. Pathog Immun. 2020;5(1):52-67. doi: 10.20411/pai.v5i1.372. PubMed PMID: 32363254; PMCID: PMC7192214.

Kayani BJ, Weaver DT, Gopalakrishnan V, King ES, Dolson E, Krishnan N, Pelesko J, Scott MJ, Hitomi M, Cadnum JL, Li DF, Donskey CJ, Scott JG, Charnas I. UV-C tower for point-of-care decontamination of filtering facepiece respirators. Am J Infect Control. 2021;49(4):424-9. doi: 10.1016/j.ajic.2020.11.010. PubMed PMID: 33186675; PMCID: PMC7654367.

Ozog DM, Sexton JZ, Narla S, Pretto-Kernahan CD, Mirabelli C, Lim HW, Hamzavi IH, Tibbetts RJ, Mi QS. The effect of ultraviolet C radiation against different N95 respirators inoculated with SARS-CoV-2. Int J Infect Dis. 2020;100:224-9. doi: 10.1016/j.ijid.2020.08.077. PubMed PMID: 32891736; PMCID: PMC7470719.

Mills D, Harnish DA, Lawrence C, Sandoval-Powers M, Heimbuch BK. Ultraviolet germicidal irradiation of influenza-contaminated N95 filtering facepiece respirators. Am J Infect Control. 2018;46(7):e49-e55. doi: 10.1016/j.ajic.2018.02.018. PubMed PMID: 29678452; PMCID: PMC7115285.

FDA. Recommendations for sponsors requesting EUAs for decontamination and bioburden reduction systems for face masks and respirators during the coronavirus disease 2019 (COVID-19) public health emergency: U.S Food and Drug Administration; 2020 [cited 2021 May 6, 2021]. Available from: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/recommendations-sponsors-requesting-euas-decontamination-and-bioburden-reduction-systems-face-masks.

FDA. Food and Drug Administration letter to 3B Medical, Inc. . U.S. Food and Drug Administration; 2020.

Standard Test Method for Determining Antimicrobial Efficacy of Ultraviolet Germicidal Irradiation against Influenza Virus on Fabric Carriers with Simulated Soil, ASTM E3179-18 (2019).

Cadnum JL, Pearlmutter BS, Redmond SN, Jencson AL, Benner KJ, Donskey CJ. Ultraviolet-C (UV-C) monitoring made simple: Colorimetric indicators to assess delivery of UV-C light by room decontamination devices. Infect Control Hosp Epidemiol. 2021:1-6. doi: 10.1017/ice.2021.113. PubMed PMID: 33858538.

Fisher EM, Richardson AW, Harpest SD, Hofacre KC, Shaffer RE. Reaerosolization of MS2 bacteriophage from an N95 filtering facepiece respirator by simulated coughing. Ann Occup Hyg. 2012;56(3):315-25. doi: 10.1093/annhyg/mer101. PubMed PMID: 22127875; PMCID: PMC7537697.

Lindsley WG, Martin SB, Jr., Thewlis RE, Sarkisian K, Nwoko JO, Mead KR, Noti JD. Effects of Ultraviolet Germicidal Irradiation (UVGI) on N95 Respirator Filtration Performance and Structural Integrity. J Occup Environ Hyg. 2015;12(8):509-17. doi: 10.1080/15459624.2015.1018518. PubMed PMID: 25806411; PMCID: PMC4699414.

O'Hearn K, Gertsman S, Sampson M, Webster R, Tsampalieros A, Ng R, Gibson J, Lobos AT, Acharya N, Agarwal A, Boggs S, Chamberlain G, Staykov E, Sikora L, McNally JD. Decontaminating N95 and SN95 masks with ultraviolet germicidal irradiation does not impair mask efficacy and safety. J Hosp Infect. 2020;106(1):163-75. doi: 10.1016/j.jhin.2020.07.014. PubMed PMID: 32687870; PMCID: PMC7367810.