Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Dec 15;8(2):ofaa610.
doi: 10.1093/ofid/ofaa610. eCollection 2021 Feb.

Validation of N95 Filtering Facepiece Respirator Decontamination Methods Available at a Large University Hospital

Krista R Wigginton  1 , Peter J Arts  1 , Herek L Clack  1 , William J Fitzsimmons  2 , Mirko Gamba  3 , Katherine R Harrison  1 , William LeBar  4 , Adam S Lauring  2 , Lucinda Li  1 , William W Roberts  5   6 , Nicole C Rockey  1 , Jania Torreblanca  4 , Carol Young  4 , Loïc G Anderegg  7   8 , Amy M Cohn  9 , John M Doyle  7   8 , Cole M Meisenhelder  7 , Lutgarde Raskin  1 , Nancy G Love  1 , Keith S Kaye  2
Affiliations

Validation of N95 Filtering Facepiece Respirator Decontamination Methods Available at a Large University Hospital

Krista R Wigginton et al. Open Forum Infect Dis. .

Abstract

Background: Due to unprecedented shortages in N95 filtering facepiece respirators, healthcare systems have explored N95 reprocessing. No single, full-scale reprocessing publication has reported an evaluation including multiple viruses, bacteria, and fungi along with respirator filtration and fit.

Methods: We explored reprocessing methods using new 3M 1860 N95 respirators, including moist (50%-75% relative humidity [RH]) heat (80-82°C for 30 minutes), ethylene oxide (EtO), pulsed xenon UV-C (UV-PX), hydrogen peroxide gas plasma (HPGP), and hydrogen peroxide vapor (HPV). Respirator samples were analyzed using 4 viruses (MS2, phi6, influenza A virus [IAV], murine hepatitis virus [MHV)]), 3 bacteria (Escherichia coli, Staphylococcus aureus, Geobacillus stearothermophilus spores, and vegetative bacteria), and Aspergillus niger. Different application media were tested. Decontaminated respirators were evaluated for filtration integrity and fit.

Results: Heat with moderate RH most effectively inactivated virus, resulting in reductions of >6.6-log10 MS2, >6.7-log10 Phi6, >2.7-log10 MHV, and >3.9-log10 IAV and prokaryotes, except for G stearothermohphilus. Hydrogen peroxide vapor was moderately effective at inactivating tested viruses, resulting in 1.5- to >4-log10 observable inactivation. Staphylococcus aureus inactivation by HPV was limited. Filtration efficiency and proper fit were maintained after 5 cycles of heat with moderate RH and HPV. Although it was effective at decontamination, HPGP resulted in decreased filtration efficiency, and EtO treatment raised toxicity concerns. Observed virus inactivation varied depending upon the application media used.

Conclusions: Both moist heat and HPV are scalable N95 reprocessing options because they achieve high levels of biological indicator inactivation while maintaining respirator fit and integrity.

Keywords: N95; decontamination; inactivation; reprocessing; virus.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
Virus inactivation on N95 respirators with pulsed xenon ultraviolet (UV) treatment. Studies A and B conducted on 2 different days. Arrows identify samples that exceeded assay detection limits after treatment. Asterisk indicates negligible inactivation. Replicates (n = 2) for each treatment condition are shown. Viruses were deposited on the coupons in either phosphate-buffered saline (PBS) or influenza A virus (IAV) media (Supplement Table S4 and Supplement Table S5). MHV, murine hepatitis virus.
Figure 2.
Figure 2.
Virus removal with moderate relative humidity (RH) heat. Virus removal with moderate RH heat using (A) Ziploc container with ~70% RH and 80°C and (B) an industrial-scale temperature and humidity-controlled oven with ~50% RH and 82°C. Replicates (n = 2) for each treatment condition are shown. Arrows identify samples that exceeded assay detection limits after treatment. Viruses were deposited on the coupons in either phosphate-buffered saline (PBS) or influenza A virus (IAV) media (Supplement Table S4 and Supplement Table S5). MHV, murine hepatitis virus.
Figure 3.
Figure 3.
Virus removal with Bioquell hydrogen peroxide vapor (HPV) system. Virus removal with Bioquell hydrogen peroxide vapor (HPV) system with either (A) Condition 1 or (B) Condition 2. Replicates of treated coupons (n = 2) are shown. Arrows illustrate samples that exceeded assay detection limits after treatment. Viruses were deposited on the coupons in either phosphate-buffered saline (PBS) or influenza A virus (IAV) media (Supplement Table S4 and Supplement Table S5). MHV, murine hepatitis virus.
See this image and copyright information in PMC

References

    1. Centers for Disease Control and Prevention. NIOSH-Approved N95 Particulate Filtering Facepiece Respirators - 3M Suppliers List Available at: https://www.cdc.gov/niosh/npptl/topics/respirators/disp_part/n95list1.html. Accessed 26 April 2020.
    1. Centers for Disease Control and Prevention. Infection Control: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Available at: https://www.cdc.gov/coronavirus/2019-ncov/hcp/infection-control-recommen.... Accessed 26 April 2020.
    1. Grossman J, Pierce A, Mody J, et al. . Institution of a novel process for N95 respirator disinfection with vaporized hydrogen peroxide in the setting of the COVID-19 pandemic at a large academic medical center. J Am Coll Surg 2020; 231:275–80. - PMC - PubMed
    1. Lore MB, Heimbuch BK, Brown TL, Wander JD, Hinrichs SH. Effectiveness of three decontamination treatments against influenza virus applied to filtering facepiece respirators. Ann Occup Hyg 2012; 56:92–101. - PubMed
    1. Heimbuch BK, Wallace WH, Kinney K, et al. . A pandemic influenza preparedness study: use of energetic methods to decontaminate filtering facepiece respirators contaminated with H1N1 aerosols and droplets. Am J Infect Control 2011; 39:e1–9. - PubMed