scholarly journals A simulation study to evaluate contamination during reuse of N95 respirators and effectiveness of interventions to reduce contamination

2021 ◽  
pp. 1-15
Author(s):  
Daniel F. Li ◽  
Heba Alhmidi ◽  
Jacob G. Scott ◽  
Ian C. Charnas ◽  
Basya Pearlmutter ◽  
...  
Keyword(s):  
Simulation Study ◽  
Healthcare Personnel ◽  
Indirect Contact ◽  
Bacteriophage Ms2 ◽  
Environmental Surfaces ◽  
Handling Technique ◽  
Correct Technique ◽  
Improved Technique ◽  
N95 Respirators ◽  
Uv C

Abstract Objective: To assess the potential for contamination of personnel, patients and the environment during use of contaminated N95 respirators and to compare the effectiveness of interventions to reduce contamination. Design: Simulation study of patient care interactions using N95 respirators contaminated with a higher and lower inoculum of the benign virus bacteriophage MS2. Methods: Twelve healthcare personnel performed 3 standardized examinations of mannequins including: 1) Control with suboptimal respirator handling technique; 2) Improved technique with glove change after each N95 contact; and 3) Control with 1-minute ultraviolet-C light (UV-C) treatment prior to donning. The order of the examinations was randomized within subject. The frequencies of contamination were compared among groups. Observations and simulations with fluorescent lotion were used to assess routes of transfer leading to contamination. Results: With suboptimal respirator handling technique, bacteriophage MS2 was frequently transferred to the participants, mannequin, and environmental surfaces and fomites. Improved technique resulted in significantly reduced transfer of MS2 in the higher inoculum simulations (P<0.01), whereas UV-C treatment reduced transfer in both the higher and lower inoculum simulations (P<0.01). Observations and simulations with fluorescent lotion demonstrated multiple potential routes of transfer to participants, mannequin, and surfaces, including both direct contact with the contaminated respirator and indirect contact via contaminated gloves. Conclusion: Reuse of contaminated N95 respirators can result in contamination of personnel and the environment even when correct technique is used. Decontamination technologies such as UV-C could reduce the risk for transmission.

scholarly journals 490. A Randomized Crossover Study to Evaluate Interventions to Reduce Contamination during Reuse of N95 Respirators

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S311-S312
Author(s):  
Daniel Li ◽  
Heba Alhmidi ◽  
Basya Pearlmutter ◽  
Jennifer Cadnum ◽  
Brigid Wilson ◽  
...  
Keyword(s):  
Crossover Study ◽  
Patient Care ◽  
Simulated Patient ◽  
Steam Treatment ◽  
Healthcare Personnel ◽  
Bacteriophage Ms2 ◽  
Correct Technique ◽  
N95 Respirators ◽  
Uv C ◽  
Randomized Crossover Study

Abstract Background During the Coronavirus Disease 2019 pandemic, shortages of personal protective equipment (PPE) have forced many healthcare facilities to require personnel to reuse N95 respirators. We hypothesized that use of correct technique such as changing gloves after N95 contact or providing rapid decontamination between each use would reduce the risk for contamination. Methods We conducted a randomized crossover study using simulated patient care interactions to compare the effectiveness of interventions to reduce contamination of personnel and the environment with high-level N95 contamination (107 plaque-forming units [PFU] of bacteriophage MS2 applied to front of respirator). Ten healthcare personnel performed 4 randomly-assigned standardized examinations of mannequins including: 1) Control (PPE donning and doffing not including glove change after N95 contact); 2) Glove change after any N95 contact; 3) Control with 1-minute ultraviolet-C light (UV-C) treatment between simulations; 4) Control with 30-second steam treatment between simulations. A second trial was conducted with groups 1–3 using a lower inoculum (105 PFU). The frequencies of participant and environmental contamination were compared. Results As shown in Figure 1.A, use of a highly contaminated N95 respirator resulted in frequent MS2 contamination in the Control, Glove change, and UV-C groups, but was dramatically reduced with steam treatment of the N95. With the lower level of contamination, MS2 contamination occurred less frequently across all groups, and was significantly reduced in the UV group, compared to the Control (Figure 1.B). Figure 1: Bacteriophage MS2 contamination during simulated patient care interactions with contaminated N95 respirators Conclusion Reuse of contaminated N95 respirators resulted in contamination of personnel and the environment even when correct technique was used. Rapid decontamination technologies can reduce the risk for transmission. Disclosures All Authors: No reported disclosures

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 COVID-19 global pandemic planning: Dry heat incubation and ambient temperature fail to consistently inactivate SARS-CoV-2 on N95 respirators

2020 ◽  
pp. 153537022097781
Author(s):  
Douglas J Perkins ◽  
Robert A Nofchissey ◽  
Chunyan Ye ◽  
Nathan Donart ◽  
Alison Kell ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Personal Protective Equipment ◽  
Healthcare Personnel ◽  
Protective Equipment ◽  
Experimental Conditions ◽  
Dry Heat ◽  
Global Pandemic ◽  
Individual Site ◽  
Pandemic Planning ◽  
N95 Respirators

The ongoing pandemic of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has placed a substantial strain on the supply of personal protective equipment, particularly the availability of N95 respirators for frontline healthcare personnel. These shortages have led to the creation of protocols to disinfect and reuse potentially contaminated personal protective equipment. A simple and inexpensive decontamination procedure that does not rely on the use of consumable supplies is dry heat incubation. Although reprocessing with this method has been shown to maintain the integrity of N95 respirators after multiple decontamination procedures, information on the ability of dry heat incubation to inactivate SARS-CoV-2 is largely unreported. Here, we show that dry heat incubation does not consistently inactivate SARS-CoV-2-contaminated N95 respirators, and that variation in experimental conditions can dramatically affect viability of the virus. Furthermore, we show that SARS-CoV-2 can survive on N95 respirators that remain at room temperature for at least five days. Collectively, our findings demonstrate that dry heat incubation procedures and ambient temperature for five days are not viable methods for inactivating SARS-CoV-2 on N95 respirators for potential reuse. We recommend that decontamination procedures being considered for the reuse of N95 respirators be validated at each individual site and that validation of the process must be thoroughly conducted using a defined protocol.

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.

scholarly journals Inactivation of Candida auris and Candida albicans by Ultraviolet-C

2020 ◽  
Vol 41 (S1) ◽  
pp. s292-s292
Author(s):  
William Rutala ◽  
Hajime Kanamori ◽  
Maria Gergen ◽  
Emily Sickbert-Bennett ◽  
David Jay Weber
Keyword(s):  
Infection Prevention ◽  
Antifungal Drugs ◽  
Candida Auris ◽  
Healthcare Facilities ◽  
Environmental Surfaces ◽  
Route Of Transmission ◽  
Indirect Exposure ◽  
Ultraviolet C ◽  
Severe Infections ◽  
Uv C

Background:Candida auris is an emerging fungal pathogen that is often resistant to major classes of antifungal drugs. It is considered a serious global health threat because it has caused severe infections with frequent mortality in over a dozen countries. C. auris can survive on healthcare environmental surfaces for at least 7 days, and it causes outbreaks in healthcare facilities. C. auris has an environmental route of transmission. Thus, infection prevention strategies, such as surface disinfection and room decontamination technologies (eg, ultraviolet [UV-C] light), will be essential to controlling transmission. Unfortunately, data are limited regarding the activity of UV-C to inactivate this pathogen. In this study, a UV-C device was evaluated for its antimicrobial activity against C. auris and C. albicans. Methods: We tested the antifungal activity of a single UV-C device using the vegetative bacteria cycle, which delivers a reflected dose of 12,000 µW/cm2. This testing was performed using Formica sheets (7.6 × 7.6 cm; 3 × 3 inches). The carriers were inoculated with C. auris or C. albicans and placed horizontal on the surface or vertical (ie, perpendicular) to the vertical UV-C lamp and at a distance from 1. 2 m (~4 ft) to 2.4 m (~8 ft). Results: Direct UV-C, with or without FCS (log10 reduction 4.57 and 4.45, respectively), exhibited a higher log10 reduction than indirect UV-C for C. auris (log10 reduction 2.41 and 1.96, respectively), which was statistically significant (Fig. 1 and Table 1). For C. albicans, although direct UV-C had a higher log10 reduction (log10 reduction with and without FCS, 5.26 and 5.07, respectively) compared to indirect exposure (log10 reduction with and without FCS, 3.96 and 3.56, respectively), this difference was not statistically significant. The vertical UV had statistically higher log10 reductions than horizontal UV against C. auris and C. albicans with FCS and without FCS. For example, for C. auris with FCS the log10 reduction for vertical surfaces was 4.92 (95% CI 3.79, 6.04) and for horizontal surfaces the log10 reduction was 2.87 (95% CI, 2.36–3.38). Conclusions:C. auris can be inactivated on environmental surfaces by UV-C as long as factors that affect inactivation are optimized (eg, exposure time). These data and other published UV-C data should be used in developing cycle parameters that prevent contaminated surfaces from being a source of acquisition by staff or patients of this globally emerging pathogen.Funding: NoneDisclosures: None

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 Applying heat and humidity using stove boiled water for decontamination of N95 respirators in low resource settings

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0255338
Author(s):  
Siddharth Doshi ◽  
Samhita P. Banavar ◽  
Eliott Flaum ◽  
Surendra Kulkarni ◽  
Ulhas Vaidya ◽  
...  
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Low Resource Settings ◽  
Low Resource ◽  
Surgical Masks ◽  
Temperature And Humidity ◽  
Similar Temperature ◽  
N95 Respirators ◽  
Electricity Access ◽  
Uv C

Global shortages of N95 respirators have led to an urgent need of N95 decontamination and reuse methods that are scientifically validated and available world-wide. Although several large scale decontamination methods have been proposed (hydrogen peroxide vapor, UV-C); many of them are not applicable in remote and low-resource settings. Heat with humidity has been demonstrated as a promising decontamination approach, but care must be taken when implementing this method at a grassroots level. Here we present a simple, scalable method to provide controlled humidity and temperature for individual N95 respirators which is easily applicable in low-resource settings. N95 respirators were subjected to moist heat (>50% relative humidity, 65–80°C temperature) for over 30 minutes by placing them in a sealed container immersed in water that had been brought to a rolling boil and removed from heat, and then allowing the containers to sit for over 45 minutes. Filtration efficiency of 0.3–4.99 μm incense particles remained above 97% after 5 treatment cycles across all particle size sub-ranges. This method was then repeated at a higher ambient temperature and humidity in Mumbai, using standard utensils commonly found in South Asia. Similar temperature and humidity profiles were achieved with no degradation in filtration efficiencies after 6 cycles. Higher temperatures (>70°C) and longer treatment times (>40 minutes) were obtained by insulating the outer vessel. We also showed that the same method can be applied for the decontamination of surgical masks. This simple yet reliable method can be performed even without electricity access using any heat source to boil water, from open-flame stoves to solar heating, and provides a low-cost route for N95 decontamination globally applicable in resource-constrained settings.

scholarly journals Effect of Glove Decontamination on Bacterial Contamination of Healthcare Personnel Hands

2019 ◽  
Vol 69 (Supplement_3) ◽  
pp. S224-S227 ◽  
Author(s):  
Zegbeh Kpadeh-Rogers ◽  
Gwen L Robinson ◽  
Haleema Alserehi ◽  
Daniel J Morgan ◽  
Anthony D Harris ◽  
...  
Keyword(s):  
Hand Hygiene ◽  
Simulation Study ◽  
Bacterial Contamination ◽  
Laboratory Simulation ◽  
Healthcare Personnel

Abstract We examined the effect of glove decontamination prior to removal on bacterial contamination of healthcare personnel hands in a laboratory simulation study. Glove decontamination reduced bacterial contamination of hands following removal. However, hand contamination still occurred with all decontamination methods, reinforcing the need for hand hygiene following glove removal.

Method for Evaluating the Relative Efficiency of Selected N95 Respirators and Surgical Masks to Prevent the Inhalation of Airborne Vegetative Cells by Healthcare Personnel

2010 ◽  
Vol 20 (2) ◽  
pp. 265-277 ◽  
Author(s):  
Craig Davidson ◽  
Christopher F. Green ◽  
Adelisa L. Panlilio ◽  
Paul A. Jensen ◽  
Beth H. Stover ◽  
...  
Keyword(s):  
Relative Efficiency ◽  
Healthcare Personnel ◽  
Vegetative Cells ◽  
Surgical Masks ◽  
N95 Respirators

scholarly journals The Emerging Nosocomial PathogensCryptosporidium, Escherichia coli0157: H7,Helicobacter pylori, and Hepatitis C: Epidemiology, Environmental Survival, Efficacy of Disinfection, and Control Measures

2001 ◽  
Vol 22 (5) ◽  
pp. 306-315 ◽  
Author(s):  
David J. Weber ◽  
William A. Rutala
Keyword(s):  
Helicobacter Pylori ◽  
Hepatitis C ◽  
Environmental Contamination ◽  
Emerging Infectious Diseases ◽  
Control Measures ◽  
Healthcare Personnel ◽  
Contact Precautions ◽  
Environmental Surfaces ◽  
Contaminated Blood ◽  
And Control

AbstractNew and emerging infectious diseases pose a threat to public health and may be responsible for nosocomial outbreaks.Cryptosporidium parvumandEscherichia coliare gastrointestina pathogens that have caused nosocomial infections via person-to-person transmission, environmental contamination, or contaminated water or food.Helicobacter pylorihas been transmitted via inadequately disinfected endoscopes. Finally, hepatitis C may be acquired by healthcare personnel by percutaneous or mucous membrane exposure to blood or between patients by use of contaminated blood products or via environmental contamination. Rigorous adherence to Standard Precautions, Contact Precautions for patients with infectious diarrhea, disinfection of environmental surfaces, and appropriate disinfection of endoscopes are adequate to prevent nosocomial acquisition of these pathogens.

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