epa tools & resources webinar: effectiveness of medical

EPA Tools and Resources Webinar: Effectiveness of Medical and Cloth Masks for COVID-19 Protection

Office of Research and Development

James M. Samet and Steven E. Prince Center for Public Health and Environmental AssessmentUS EPA Office of Research and Development (ORD)

January 27, 2021

Since March 2020, EPA ORD and University of North Carolina (UNC) Center for Environmental Medicine, Asthma and Lung Biology (CEMALB) investigators have completed 3 research projects on the efficiency of face coverings used as personal protection against infection with the SARS-CoV-2 virus:

Overview

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Sources:1. Sickbert-Bennett, E.E., Samet, J.M., Clapp, P.W., et al., JAMA Intern Med. 2020;180(12):1607-1612. doi:10.1001/jamainternmed.2020.4221. Published online August 11, 20202. Clapp, P.W., Sickbert-Bennett, E.E., Samet, J.M., et al. JAMA Intern Med. doi:10.1001/jamainternmed.2020.8168, Published online December 10, 20203. Prince, S.E., Chen, H., Tong, H., et al., Submitted

1. A comparative study of the performance of respirator alternatives available to hospitals during the COVID-19 pandemic

2. An evaluation of the efficiency of face coverings worn by the public during the COVID-19 pandemic

3. An examination of the effect of beard hair on the performance of face coverings used during the COVID-19 pandemic

Project 1: A comparative study of the performance of respirator alternatives available to hospitals during the COVID-19 pandemic

• UNC Hospitals staff faced an urgent, acute shortage of disposable N95 respirators caused by a nationwide shortage in supply and a sharp increase in demand caused by the emerging COVID-19 pandemic in the US (March 2020).

• Hospital infection control staff approached our colleagues with the EPA-UNC Cooperative Agreement for assistance evaluating the performance of respirators that had been sterilized, were past their expiration date or mis-sized, as well as an extensive series of respirator alternative and prototypes being sourced from around the globe.

Problem

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UNC IRB#19-2078

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MPF, Inc.

Eligibilityscreeningby phone

Mask Questionnaire• Previous

experience and training

• Attitude and disposition survey

Fit Test 1No instruction provided

Medical Station

• Teleconferenced Informed consent

• Pregnancy Test• Vital signs

MASKFITUNC IRB#19-2078

Version July 4, 2020

MedicalStaff

Phase 1-Physical Exam

}

Conducted under IRB # 95-018

Fit Test 2Subject provided product instructions included in packaging by manufacturer

Fit Test 3Subject shown an instructional video presentation on donning and doffing of N95 masks

Fit Test 4Study staff will inspect mask fit for visible errors and retest as needed

Room 79/ Chamber IA79

Pre-enrollment Qualification

Enrollment and Participation

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Approach


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Test System Overview

• The fit test conducted is the Occupation Safety and Health Administration (OSHA) Modified Ambient Aerosol CNC Quantitative Fit Testing Protocol for Full Facepiece and Half-Mask Elastomeric Respirators (29 CFR 1910, Table A-1).

• A TSI 8026 Particle Generator designed for respirator fit testing was used to supplement ambient particle counts with NaCl particles with a count median diameter of 0.04 um.

• Particle counts in chamber IA79 are allowed to stabilize for 30 minutes prior to testing. Chamber particle counts are in typically in the range of 6000-9000, meaning that 95% reduction results in counts of 300 or above, with instrument range to spare to accurately detect filtering performance of ≥ to 99%.

• All masks/respirators are fitted with sampling probes using a TSI model 8025-N95 Fit Test Probe Kit.

• A pair of butanol-based TSI 3775 Condensation Particle Counters are used to continuously monitor the chamber and behind the respirator/mask with 1 second averaging over the testing period.

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Attachment 2

TABLE A–2— MODIFIED AMBIENT AEROSAL CNC QUANTITATIVE FIT TESTING PROTOCOL FOR FILTERING FACEPIECE RESPIRATORS

Exercises1 Exercise procedure Measurement

procedure

Bending Over ........... The test subject shall bend at the waist, as if going to touch his/her toes for 50 seconds and inhale 2 times at the bottom2. A 20 second ambient sample, followed

by a 30 second mask sample. Talking ...................... The test subject shall talk out loud slowly and loud enough so as to be heard

clearly by the test conductor for 30 seconds. He/she will either read from a prepared text such as the Rainbow Passage, count backward from 100, or recite a memorized poem or song.

A 30 second mask sample.

Head Side-to-Side .... The test subject shall stand in place, slowly turning his/her head from side to side for 30 seconds and inhale 2 times at each extreme2.


Head Up-and-Down The test subject shall stand in place, slowly moving his/her head up and down for 39 seconds and inhale 2 times at each extreme2.

A 30 second mask sample followed by a 9 second ambient sample.

1Exercises are listed in the order in which they are to be administered. 2It is optional for test subjects to take additional breaths at other times during this exercise.

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ResultsProject 1: A comparative study of the performance of respirator

alternatives available to hospitals during the COVID-19 pandemic

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Evaluation of Fitted Filtration Efficiency(FFE) Using the Occupational Safety andHealth Administration Modified AmbientAerosol CNC Quantitative Fit TestingProtocol for Filtering FacepieceWhen usedon a man, the overall FFE for a NationalInstitute for Occupational Safety andHealth–approved N95 respirator was 98.5%(A), the overall FFE of a surgical mask withties was 71.5% (B), and the overall FFE ofa procedural mask with elastic ear loopswas 38.1% (C). Data correspond to particlepenetration into the face mask asexpressed as the percentage of totalparticle/cc measured simultaneouslyoutside of the face mask.

Sickbert-Bennett, E, Samet, JM, Clapp, PW, et al..,JAMA Intern Med. 2020;180(12):1607-1612. doi:10.1001/jamainternmed.2020.4221 Published online August 11, 2020.

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A Graphical View of Fitted Filtration Efficiency (FFE) of Face Coverings Commonly Worn in Health Care Settings


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Face Mask Fitted Filtration Efficiency (FFE) Against Submicron Particle Penetrationa The FFE percentage corresponds to the mask condensation particle counter counts/ambient condensation particle counter counts × 100. The FFE percentage and SD were calculated across the length of the test.b Mask functioned at or above 95% FFE.


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Impact

• This study evaluated 29 face covering alternatives and practices for use by hospitals facing acute shortages of respirators worn by health care providers working with COVID-19 patients, showing that respirators can retain their effectiveness after sterilization and long past their expiration date, and that, although variable, some foreign sourced masks approximate the performance of NIOSH-rated respirators.

• This information can guide infection control professionals in prioritizing the supply of available PPE during emergencies.


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Problem

• During the pandemic, the public is advised to wear face coverings as a primary protective measure to combat the transmission of the SARS-CoV-2 virus.

• A broad variety of face coverings have been adopted, ranging from improvised and home-made designs to mass-produced disposable or reusable masks, of varying material and construction, marketed to the consumer. However, little guidance or information exists on the comparative effectiveness of these face coverings.

• Similarly, while a number of modifications or “hacks” designed to improve the performance of inexpensive surgical or procedure style disposable masks have been reported in the media, independent evaluation of their usefulness is lacking.

Project 2: An evaluation of the efficiency of face coverings worn by the public during the COVID-19 pandemic

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Approach


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*

Attachment 2



procedure










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Results


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Consumer-Grade Masks and Improvised Face CoveringsThe facecoverings tested in this study included a 2-layer woven nylon mask withear loops (54% recycled nylon, 43% nylon, 3% spandex), tested withand without an optional aluminum nose bridge and nonwoven filterinsert in place (A), a cotton bandana folded diagonally once “bandit”style (B), a cotton bandana folded in a multilayer rectangle according tothe instructions presented by the US Surgeon General (C), a single-layer woven polyester/nylon mask (80% polyester, 17% nylon, 3%spandex) with ties (D), a nonwoven polypropylene mask with fixed earloops (E), a single-layer woven gaiter/neck cover balaclava bandana(92% polyester and 8% spandex) (F), and a 3-layer woven cotton mask(100% cotton) with ear loops (G).

Clapp, P.W., Sickbert-Bennett, E.E., Samet, J.M, et al., JAMA Intern Med. Published online December 10, 2020. doi:10.1001/jamainternmed.2020.816820

44-79 % FFE 49 % FFE

26 % FFE

49 % FFE

29 % FFE 38 % FFE

39 % FFE


Medical Procedure Mask and Modifications Designed toEnhance Mask Fit or Comfort for the WearerA medicalprocedure mask with ear loops (A) was modified by tyingthe ear loops and tucking in the side pleats (B), attachingear loops to a 3-dimensional–printed “ear guard” (C),fastening ear loops with a 23-mm claw-type hair clip placedbehind the wearer’s head (D), placing a ring of 3 gangedrubber bands over the mask and around the wearer’s ears(E), and sliding a 10-inch segment of nylon hosiery overthe fitted procedure mask (F).

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38 % FFE

78 % FFE65 % FFE

62 % FFE60 % FFE

80 % FFE

Face Mask FFE Against Submicron Particle Penetration- Abbreviations: FFE, fittedfiltration efficiency; NIOSH, National Institute for Occupational Safety and Health.a The percentage of FFE corresponds to 100 × (1 − behind the mask particleconcentration / ambient particle concentration). Overall FFE percentage and SDwere calculated across the length of the test.


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Evaluation of Fitted Filtration Efficiency (FFE) Using the USOccupational Safety and Health Administration Modified AmbientAerosol CNC Quantitative Fit Testing Protocol for FilteringFacepieceThe overall FFE for a medical procedure mask with earloops (A), medical procedure mask with the ear loops tied andmask corners tucked against the wearer’s face (B), and 2-layerwoven nylon mask with an aluminum nose bridge and 1 nonwovenfilter insert (C) was 38.5%, 60.3%, and 74.4%, respectively.Particle penetration (y-axes) is defined as particle concentrationbehind the mask expressed as a percentage of the ambientparticle concentration and is calculated during repeated-movementtests (bending at the waist, reading aloud, looking left and right,and looking up and down). The overall percentage of FFE isdefined as 100 × (1 − behind the mask particleconcentration / ambient particle concentration). Overall FFEpercentage and SD were calculated across the length of the test.L/R indicates left/right; U/D, up/down.


A Graphical View of the Fitted Filtration Efficiency (FFE) of Selected Face Coverings Worn by the

Public During the COVID-19 Pandemic

Impact

• This study provides information on the relative respiratory protection afforded by a range of reusable cloth face coverings representative of those available to the American public during the COVID-19 pandemic and evaluated the effectiveness of modifications reported to improve the performance of disposable surgical/procedure style masks.

• The findings of this study can guide the public in the selection of face coverings that offer optimal performance relative to other attributes such as cost, convenience and environmental impact.


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Problem

• Over 60 percent of American men report keeping a beard at least occasionally as personal preference, cultural norm, religious imperative or medical necessity.

• While most beard styles are contraindicated for N95 respirator fit testing, there is very limited information about the impact of beard hair on the performance of other types of facial coverings worn by the public for respiratory protection against transmission of the SARS-CoV-2 virus.

Project 3: An examination of the effect of beard hair on the performance of face coverings used during the COVID-19 pandemic

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ApproachProject 3: An examination of the effect of beard hair on the

performance of face coverings used during the COVID-19 pandemic

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*

Attachment 2



procedure










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The same efficiency testing procedure, including the 4 exercises below were used:

Prince, S.E., Chen, H., Tong, H., et al., 2020, Submitted29

Beard hair lengths in 0.5 mm increments (0-10mm), Full beard, Exercise band coverings

Results


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Respirator fitted filtration efficiency (FFE) against submicron particles for shaved and unshaven men shows interindividual variability

Note: a The efficiency is calculated as [1- (mask count/ambient count)] *100 across the length of the test. The FFE ± SD are shown. Prince, S.E., Chen, H., Tong, H., et al., 2020, Submitted

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• N95 efficiency was higher overall for clean shaven men and more variable for bearded men

Beard hair length differentially affects face coverings


With increasing beard hair length, efficiency:• Decreased for respirator-type masks• Relatively unchanged for cloth and procedure masks


Fitted Filtering Efficiency of Face Coverings as a Function of Beard Hair Length Varies Between Face Coverings

• N95 efficiency was highest overall followed by KF94 and KN95 masks

• Performance declined with increasing beard hair length

• Cloth and procedure masks had the lowest overall efficiency

• Relatively stable across beard hair lengths

The effect of an elastic band worn over the beard on the fitted filtration efficiency of various face coverings

Note: a The efficiency (FFE) is calculated as [1- (mask count/ambient count)] *100 across the length of the test. The FFE ± SD are shown. The average of at least 2 unique tests were presented. b % improvement was calculated as the percentage increase of FFE with and without the elastic band.


Impact

• Given the high prevalence of beards among American men, the finding in this study that beard hair can impair the performance of a variety of face coverings worn for protection against SARS-CoV-2 infection represents a potential limitation on the effectiveness of face coverings as an interventional approach to control the spread of COVID-19.

• The mitigation of the effect of beard hair on face covering performance with a simple exercise resistance band offers a potential solution to individuals for whom a beard is personal, cultural, religious or medical necessity.


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Take Home Messages

• This research ranked the fitted performance of alternative face coverings and practices available in health care settings to guide decisions during shortages in the supply of respirators. Specifically: • NIOSH-certified respirators retain their efficiency after sterilization and past their expiration date.• Although there is considerable variability, the performance of some foreign sourced masks can match that of NIOSH-

certified respirators.

• A comparison of face coverings and mask modifications available during the COVID-19 pandemic informs the public on the best options for protection from SARS-CoV-2 infection. • Modifications to improve the fit of surgical style masks can be effective in improving their filtration efficiency. • While highly variable, cloth masks can offer protection comparable to that of surgical style masks.

• Given its prevalence in the population, facial hair represents a potentially significant limitation on the efficacy of face coverings as an interventional approach to provide respiratory protection during emergencies. • NIOSH-certified respirators showed the greatest tolerance to beard hair, followed by other high-efficiency masks that

outperform surgical and cloth masks.• A simple elastomeric band worn over the beard can significantly improve the filtration efficiency of face coverings.

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James M. Samet PhD MPH DABT

Senior Principal InvestigatorPublic Health and Integrated Toxicology DivisionCenter for Public Health and Environmental AssessmentUS EPA Office of Research and [email protected] 451-0565

Contact

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The views expressed in this presentation are those of the author and do not necessarily reflect the views or policies of the US EPA

Any mention of trade names or commercial products does not constitute EPA endorsement or recommendation for use.3737

US EPA ORD Haiyan Tong, MD, PhDHao Chen, PhD (ORISE)David Diaz-Sanchez, PhD

UNC Center for Environmental Medicine and Lung BiologyWilliam D. Bennett, PhDPhilip W. Clapp, PhDKirby L. Zeman, PhD

UNC HospitalsEmily E. Sickbert-Bennett, PhDDavid J. Weber, MD, MPH

TRCJon Berntsen, PhD

Acknowledgements

Steven E. Prince PhD

Principal InvestigatorPublic Health and Environmental Systems DivisionCenter for Public Health and Environmental AssessmentUS EPA Office of Research and [email protected] 966-8901

mailto:[email protected]

mailto:[email protected]

Emily Haiyan

epa tools & resources webinar: effectiveness of medical

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