scholarly journals Mapping of UV-C dose and SARS-CoV-2 viral inactivation across N95 respirators during decontamination

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alisha Geldert ◽  
Alison Su ◽  
Allison W. Roberts ◽  
Guillaume Golovkine ◽  
Samantha M. Grist ◽  
...  
Keyword(s):  
Optical Simulation ◽  
Pathogen Inactivation ◽  
Viral Inactivation ◽  
Flexible Form ◽  
Measurement Tools ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C ◽  
Dose Difference

AbstractDuring public health crises like the COVID-19 pandemic, ultraviolet-C (UV-C) decontamination of N95 respirators for emergency reuse has been implemented to mitigate shortages. Pathogen photoinactivation efficacy depends critically on UV-C dose, which is distance- and angle-dependent and thus varies substantially across N95 surfaces within a decontamination system. Due to nonuniform and system-dependent UV-C dose distributions, characterizing UV-C dose and resulting pathogen inactivation with sufficient spatial resolution on-N95 is key to designing and validating UV-C decontamination protocols. However, robust quantification of UV-C dose across N95 facepieces presents challenges, as few UV-C measurement tools have sufficient (1) small, flexible form factor, and (2) angular response. To address this gap, we combine optical modeling and quantitative photochromic indicator (PCI) dosimetry with viral inactivation assays to generate high-resolution maps of “on-N95” UV-C dose and concomitant SARS-CoV-2 viral inactivation across N95 facepieces within a commercial decontamination chamber. Using modeling to rapidly identify on-N95 locations of interest, in-situ measurements report a 17.4 ± 5.0-fold dose difference across N95 facepieces in the chamber, yielding 2.9 ± 0.2-log variation in SARS-CoV-2 inactivation. UV-C dose at several on-N95 locations was lower than the lowest-dose locations on the chamber floor, highlighting the importance of on-N95 dose validation. Overall, we integrate optical simulation with in-situ PCI dosimetry to relate UV-C dose and viral inactivation at specific on-N95 locations, establishing a versatile approach to characterize UV-C photoinactivation of pathogens contaminating complex substrates such as N95s.

scholarly journals Non-uniform UV-C dose across N95 facepieces can cause 2.9-log variation in SARS-CoV-2 inactivation

2021 ◽  
Author(s):  
Alisha Geldert ◽  
Alison Su ◽  
Allison W. Roberts ◽  
Guillaume Golovkine ◽  
Samantha M. Grist ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Optical Simulation ◽  
Viral Inactivation ◽  
Flexible Form ◽  
Measurement Tools ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C ◽  
Dose Difference

AbstractDuring public health crises like the COVID-19 pandemic, ultraviolet-C (UV-C) decontamination of N95 respirators for emergency reuse has been implemented to mitigate shortages. However, decontamination efficacy across N95s is poorly understood, due to the dependence on received UV-C dose, which varies across the complex three-dimensional N95 shape. Robust quantification of UV-C dose across N95 facepieces presents challenges, as few UV-C measurement tools have sufficient 1) small, flexible form factor, and 2) angular response. To address this gap, we combine optical modeling and quantitative photochromic indicator (PCI) dosimetry with viral inactivation assays to generate high-resolution maps of “on-N95” UV-C dose and concomitant SARS-CoV-2 viral inactivation across N95 facepieces within a commercial decontamination chamber. Using modeling to rapidly identify on-N95 locations of interest, in-situ measurements report a 17.4 ± 5.0-fold dose difference across N95 facepieces, yielding 2.9 ± 0.2-log variation in SARS-CoV-2 inactivation. UV-C dose at several on-N95 locations was lower than the lowest-dose locations on the chamber floor, highlighting the importance of on-N95 dose validation. Overall, we couple optical simulation with in-situ PCI dosimetry to relate UV-C dose and viral inactivation at specific

scholarly journals Effectiveness of Ultraviolet-C Light and a High-Level Disinfection Cabinet for Decontamination of N95 Respirators

2020 ◽  
Vol 5 (1) ◽  
pp. 52 ◽  
Author(s):  
Jennifer L. Cadnum ◽  
Daniel Li ◽  
Sarah N. Redmond ◽  
Amrita R. John ◽  
Basya Pearlmutter ◽  
...  
Keyword(s):  
Methicillin Resistant Staphylococcus Aureus ◽  
Test Method ◽  
Dry Heat ◽  
Ultraviolet C ◽  
Multiple Cycles ◽  
American Society ◽  
High Level ◽  
N95 Respirators ◽  
Uv C ◽  
Disk Test

Background-Shortages of personal protective equipment (PPE) including N95 filtering facepiece respirators is an urgent concern in the setting of the global COVID-19 pandemic.  Decontamination of PPE could be useful to maintain adequate supplies, but there is uncertainty regarding the efficacy of decontamination technologies.Methods-A modification of the American Society for Testing and Materials standard quantitative carrier disk test method (ASTM E-2197-11) was used to examine the effectiveness of ultraviolet-C (UV-C) light, a high-level disinfection cabinet that generates aerosolized peracetic acid and hydrogen peroxide, and dry heat at 70°C for 30 minutes for decontamination of bacteriophages Phi6 and MS2 and methicillin-resistant Staphylococcus aureus (MRSA) inoculated onto 3 commercial N95 respirators.  Three and 6 log10 reductions on N95 respirators were considered effective for decontamination and disinfection, respectively. Results-UV-C administered as a 1-minute cycle in a UV-C box or a 30-minute cycle by a room decontamination device reduced contamination but did not meet criteria for decontamination of the viruses from all sites for any of the N95s.  The high-level disinfection cabinet was effective for decontamination of all the organisms from the N95s and achieved disinfection with 3 disinfection cycles over ~60 minutes.  Dry heat at 70°C for 30 minutes was not effective for decontamination of the bacteriophages.  Conclusions-UV-C could be useful to reduce contamination on N95 respirators.  However, the UV-C technologies studied did not meet our criteria for decontamination under the test conditions used.  The high-level disinfection cabinet was effective for decontamination of N95s and met criteria for disinfection with multiple cycles.

scholarly journals Practical considerations for Ultraviolet-C radiation mediated decontamination of N95 respirator against SARS-CoV-2 virus

2020 ◽  
Author(s):  
Guillaume R. Golovkine ◽  
Allison W. Roberts ◽  
Chase Cooper ◽  
Sebastian Riano ◽  
Angela M. DiCiccio ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Model Material ◽  
Efficacy Data ◽  
Light Emitting ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C ◽  
Disinfection Chamber

AbstractDecontaminating N95 respirators for reuse could mitigate shortages during the COVID-19 pandemic. We tested a portable UV-C light-emitting diode disinfection chamber and found that decontamination efficacy depends on mask model, material and location on the mask. This emphasizes the need for caution when interpreting efficacy data of UV-C decontamination methods.

scholarly journals Practical considerations for Ultraviolet-C radiation mediated decontamination of N95 respirator against SARS-CoV-2 virus

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258336
Author(s):  
Guillaume R. Golovkine ◽  
Allison W. Roberts ◽  
Chase Cooper ◽  
Sebastian Riano ◽  
Angela M. DiCiccio ◽  
...  
Keyword(s):  
United States ◽  
Light Emitting Diode ◽  
The United States ◽  
Model Material ◽  
Efficacy Data ◽  
Light Emitting ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C ◽  
Disinfection Chamber

Decontaminating N95 respirators for reuse could mitigate shortages during the COVID-19 pandemic. Although the United States Center for Disease Control has identified Ultraviolet-C irradiation as one of the most promising methods for N95 decontamination, very few studies have evaluated the efficacy of Ultraviolet-C for SARS-CoV-2 inactivation. In addition, most decontamination studies are performed using mask coupons that do not recapitulate the complexity of whole masks. We sought to directly evaluate the efficacy of Ultraviolet-C mediated inactivation of SARS-CoV-2 on N95 respirators. To that end we created a portable UV-C light-emitting diode disinfection chamber and tested decontamination of SARS-CoV-2 at different sites on two models of N95 respirator. We found that decontamination efficacy depends on mask model, material and location of the contamination on the mask. Our results emphasize the need for caution when interpreting efficacy data of UV-C decontamination methods.

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

2021 ◽  
Vol 6 (1) ◽  
pp. 104-115
Author(s):  
Jennifer Cadnum ◽  
Basya Pearlmutter ◽  
Daniel Li ◽  
Annette Jencson ◽  
Jacob Scott ◽  
...  
Keyword(s):  
Limited Information ◽  
Bacterial Strains ◽  
Bacteriophage Ms2 ◽  
Different Types ◽  
Reduction Methods ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C

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. 

scholarly journals UV-A and UV-B Can Neutralize SARS-CoV-2 Infectivity

2021 ◽  
Author(s):  
Mara Biasin ◽  
Sergio Strizzi ◽  
Andrea Bianco ◽  
Alberto Macchi ◽  
Olga Utyro ◽  
...  
Keyword(s):  
Uv Light ◽  
Action Spectrum ◽  
Summer Season ◽  
Solar Irradiation ◽  
Viral Inactivation ◽  
Violet Light ◽  
Depth Analysis ◽  
Virucidal Effect ◽  
Uv C

We performed an in-depth analysis of the virucidal effect of discrete wavelengths: UV-C (278 nm), UV-B (308 nm), UV-A (366 nm) and violet (405 nm) on SARS-CoV-2. By using a highly infectious titer of SARS-CoV-2 we observed that the violet light-dose resulting in a 2-log viral inactivation is only 10-4 times less efficient than UV-C light. Moreover, by qPCR and fluorescence in situ hybridization (FISH) approach we verified that the viral titer typically found in the sputum of COVID-19 patients can be completely inactivated by the long UV-wavelengths corresponding to UV- A and UV-B solar irradiation. The comparison of the UV action spectrum on SARS-CoV-2 to previous results obtained on other pathogens suggests that RNA viruses might be particularly sensitive to long UV wavelengths. Our data extend previous results showing that SARS-CoV-2 is highly susceptible to UV light and offer an explanation to the reduced incidence of SARS-CoV-2 infection seen in the summer season.

scholarly journals Approach of using a household device in decontaminating respirators with  ultraviolet C during the scarcity in the COVID-19 pandemic

2020 ◽  
Author(s):  
Darunee Chotiprasitsakul ◽  
Taya Kitiyakara ◽  
Anan Jongkaewwattana ◽  
Pitak Santanirand ◽  
Atisak Jiaranaikulwanich ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Bacterial Culture ◽  
Polymer Fibers ◽  
Baby Bottle ◽  
Before And After ◽  
Ultraviolet C ◽  
N95 Respirators ◽  
Uv C ◽  
Scanning Electron

Abstract Background Reusing N95 respirators with a practical and easy decontamination protocol might be a solution for the shortage of N95 respirators. We aimed to study the reliability and safety of household UV-C devices for the decontamination of N95 respirators. Methods We investigated a baby bottle ultraviolet C (UV-C) sterilizer box for N95 decontamination. Swine coronavirus (PEDV) was sprayed on the N95 and the virus was cultivated after UV-C sterilization. Bacterial culture from used N95 respirator was performed before and after UV-C exposure. Scanning electron Microscopy (SEM) was used to observe the structural change after UV-C exposure. The radiation was measured by radiometer. The fit test was performed on 3 participants before use, and after reuse 4 and 6 times. Results The PEDV sprayed on the N95 respirator was inactivated by the UV-C level of 0.930–0.932 mW/cm2. Nearly all bacterial colonies had disappeared after the 10 min of the UV-C exposure. No significant change to the structure of the N95 polymer fibers after 240 min of UV-C exposure was observed by SEM. Three and two participants passed the fit test after the fourth and sixth time of reuse, respectively. Conclusions During the COVID-19 pandemic crisis, UV-C products may be practical and safe options for decontaminating N95 respirators, if the energy of UV-C is in the range known to deactivate the virus.

scholarly journals Effectiveness of Ultraviolet-C Room Disinfection on Preventing Healthcare-Associated Clostridioides difficile Infection

2020 ◽  
Vol 41 (S1) ◽  
pp. s33-s33
Author(s):  
Michihiko Goto ◽  
Erin Balkenende ◽  
Gosia Clore ◽  
Rajeshwari Nair ◽  
Loretta Simbartl ◽  
...  
Keyword(s):  
Acute Care ◽  
Acute Care Hospitals ◽  
Incidence Rates ◽  
Positive Test ◽  
Negative Binomial Regression Model ◽  
Test Results ◽  
Clostridioides Difficile ◽  
Ultraviolet C ◽  
Healthcare Associated ◽  
Uv C

Background: Enhanced terminal room cleaning with ultraviolet C (UVC) disinfection has become more commonly used as a strategy to reduce the transmission of important nosocomial pathogens, including Clostridioides difficile, but the real-world effectiveness remains unclear. Objectives: We aimed to assess the association of UVC disinfection during terminal cleaning with the incidence of healthcare-associated C. difficile infection and positive test results for C. difficile within the nationwide Veterans Health Administration (VHA) System. Methods: Using a nationwide survey of VHA system acute-care hospitals, information on UV-C system utilization and date of implementation was obtained. Hospital-level incidence rates of clinically confirmed hospital-onset C. difficile infection (HO-CDI) and positive test results with recent healthcare exposures (both hospital-onset [HO-LabID] and community-onset healthcare-associated [CO-HA-LabID]) at acute-care units between January 2010 and December 2018 were obtained through routine surveillance with bed days of care (BDOC) as the denominator. We analyzed the association of UVC disinfection with incidence rates of HO-CDI, HO-Lab-ID, and CO-HA-LabID using a nonrandomized, stepped-wedge design, using negative binomial regression model with hospital-specific random intercept, the presence or absence of UVC disinfection use for each month, with baseline trend and seasonality as explanatory variables. Results: Among 143 VHA acute-care hospitals, 129 hospitals (90.2%) responded to the survey and were included in the analysis. UVC use was reported from 42 hospitals with various implementation start dates (range, June 2010 through June 2017). We identified 23,021 positive C. difficile test results (HO-Lab ID: 5,014) with 16,213 HO-CDI and 24,083,252 BDOC from the 129 hospitals during the study period. There were declining baseline trends nationwide (mean, −0.6% per month) for HO-CDI. The use of UV-C had no statistically significant association with incidence rates of HO-CDI (incidence rate ratio [IRR], 1.032; 95% CI, 0.963–1.106; P = .65) or incidence rates of healthcare-associated positive C. difficile test results (HO-Lab). Conclusions: In this large quasi-experimental analysis within the VHA System, the enhanced terminal room cleaning with UVC disinfection was not associated with the change in incidence rates of clinically confirmed hospital-onset CDI or positive test results with recent healthcare exposure. Further research is needed to understand reasons for lack of effectiveness, such as understanding barriers to utilization.Funding: NoneDisclosures: None

scholarly journals Ultraviolet-C as a Viable Reprocessing Method for Disposable Masks and Filtering Facepiece Respirators

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 801
Author(s):  
Talita Nicolau ◽  
Núbio Gomes Filho ◽  
Andrea Zille
Keyword(s):  
Literature Review ◽  
Systematic Literature Review ◽  
Personal Protective Equipment ◽  
State Of The Art ◽  
Protective Equipment ◽  
Multiple Methods ◽  
Ultraviolet C ◽  
Single Use ◽  
Uv C ◽  
New Strategies

In normal conditions, discarding single-use personal protective equipment after use is the rule for its users due to the possibility of being infected, particularly for masks and filtering facepiece respirators. When the demand for these protective tools is not satisfied by the companies supplying them, a scenario of shortages occurs, and new strategies must arise. One possible approach regards the disinfection of these pieces of equipment, but there are multiple methods. Analyzing these methods, Ultraviolet-C (UV-C) becomes an exciting option, given its germicidal capability. This paper aims to describe the state-of-the-art for UV-C sterilization in masks and filtering facepiece respirators. To achieve this goal, we adopted a systematic literature review in multiple databases added to a snowball method to make our sample as robust as possible and encompass a more significant number of studies. We found that UV-C’s germicidal capability is just as good as other sterilization methods. Combining this characteristic with other advantages makes UV-C sterilization desirable compared to other methods, despite its possible disadvantages.

scholarly journals Integrated photothermal decontamination device for N95 respirators

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marcelo Muñoz ◽  
Maxime Comtois-Bona ◽  
David Cortes ◽  
Cagla Eren Cimenci ◽  
Qiujiang Du ◽  
...  
Keyword(s):  
Low Income ◽  
Temperature Treatment ◽  
Low Income Countries ◽  
Effective Vaccine ◽  
Global Pandemic ◽  
Photothermal Treatment ◽  
Mild Temperature ◽  
N95 Respirators ◽  
Uv C

AbstractThe severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) responsible for the COVID-19 global pandemic has infected over 25 million people worldwide and resulted in the death of millions. The COVID-19 pandemic has also resulted in a shortage of personal protective equipment (PPE) in many regions around the world, particularly in middle- and low-income countries. The shortages of PPE, such as N95 respirators, is something that will persist until an effective vaccine is made available. Thus, devices that while being easy to operate can also be rapidly deployed in health centers, and long-term residences without the need for major structural overhaul are instrumental to sustainably use N95 respirators. In this report, we present the design and validation of a decontamination device that combines UV-C & B irradiation with mild-temperature treatment. The device can decontaminate up to 20 masks in a cycle of < 30 min. The decontamination process did not damage or reduce the filtering capacity of the masks. Further, the efficacy of the device to eliminate microbes and viruses from the masks was also evaluated. The photothermal treatment of our device was capable of eradicating > 99.9999% of the bacteria and > 99.99% of the virus tested.

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