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Comment & Response
November 23, 2020

Poor Performance of Masks Secured Using Ear Loops

Author Affiliations
  • 1Infectious Disease Service, KK Women’s and Children’s Hospital, Singapore
  • 2Lee Kong Chian School of Medicine, Imperial College, Nanyang Technological University, Singapore
  • 3Duke-NUS Medical School, Singapore
JAMA Intern Med. 2021;181(2):294. doi:10.1001/jamainternmed.2020.6393

To the Editor The Original Investigation by Sickbert-Bennett and colleagues1 provides much-needed data to help ensure that health care professionals caring for patients with respiratory viral illness are provided with an effective mask for respiratory protection.2,3 Importantly, their results may also provide insights that could guide future design of masks, especially in terms of how they are held in place on the user’s face. They also highlight the need to expand mask approval criteria beyond mask filter performance.

When comparing a surgical mask with head ties vs a procedure mask with ear loops, there was a large difference in fitted filtration efficiencies (FFEs) (71.5% v 38.1%, respectively).1 Even more worrying, there was also a similar trend of poor FFE performance for N95 respirators designed with ear loops vs those with head straps. The bottom 6 FFE-performing N95 respirators in their Table 11 results used ear loops to hold the mask in place on the user’s face, and they all had less than 90% FFE.1 The FFE performance of surgical masks secured with head ties within 1 SD would have a range of 66% to 77%. This would overlap with the FFE performance of 4 out of the 6 bottom N95 respirators secured using ear loops (within 1 SD).1 Currently, N95 respirators are usually prioritized for high-risk exposures, including when performing aerosol-generating procedures, and these findings show that health care workers using N95 respirators secured with ear loops may not have better protection than those using a surgical mask secured with head ties.

Data on the actual mask filter performance were not reported, and only 1 surgical/procedure mask with head ties/ear loop was included in the study. The former’s potential bias is important to exclude, as actual mask filter performance can vary significantly from manufacturer-reported filtration efficiencies.4 However, if these findings can be confirmed to be consistent, future design and manufacture of N95 respirators may need to exclude ear loops altogether. The current approval process with a focus on mask filter performance may also need to be updated, to consider how they are held in place. From a physics perspective, the forces generated by elastic ear loops are unlikely to be stronger than head ties or straps, which are needed to ensure better fit on the user’s face, especially for N95 respirators.

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Article Information

Corresponding Author: Chee Fu Yung, MBChB, MSt, 100 Bukit Timah Rd, Infectious Disease Service, KK Women’s and Children’s Hospital, Singapore 229899 (yung.chee.fu@singhealth.com.sg).

Published Online: November 23, 2020. doi:10.1001/jamainternmed.2020.6393

Conflict of Interest Disclosures: None reported.

Editorial Note: This letter was shown to the corresponding author of the original article, who declined to reply on behalf of the authors.

References
1.
Sickbert-Bennett  EE, Samet  JM, Clapp  PW,  et al.  Filtration efficiency of hospital face mask alternatives available for use during the COVID-19 pandemic.   JAMA Intern Med. Published online August 11, 2020. doi:10.1001/jamainternmed.2020.4221PubMedGoogle Scholar
2.
Offeddu  V, Yung  CF, Low  MSF, Tam  CC.  Effectiveness of masks and respirators against respiratory infections in healthcare workers: a systematic review and meta-analysis.   Clin Infect Dis. 2017;65(11):1934-1942. doi:10.1093/cid/cix681PubMedGoogle ScholarCrossref
3.
Tong  WY, Yung  CF, Chiew  LC,  et al.  universal face masking reduces respiratory viral infections among inpatient very-low-birthweight neonatal infants.   Clin Infect Dis. 2020;ciaa555. doi:10.1093/cid/ciaa555PubMedGoogle Scholar
4.
Oberg  T, Brosseau  LM.  Surgical mask filter and fit performance.   Am J Infect Control. 2008;36(4):276-282. doi:10.1016/j.ajic.2007.07.008PubMedGoogle ScholarCrossref
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    2 Comments for this article
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    Re: Poorly fitting ear loop face masks
    Anne Tonti-Filippini, Master of Pharmacy | Retired (2019) Hospital Pharmacist
    Researching the fit characteristics of face masks & face shields is one of my favourite topics and this excellent article is much appreciated for its clarity.
    I retired from hospital pharmacy 18 months ago, in the pre-coronavirus era. At that time, standard surgical masks with head ties were the norm on the wards, except in the negative pressure rooms, where additional & higher quality PPE was worn.
    However, when compounding injectable chemotherapy in the pharmacy's sterile suite, we always wore "Cytoguard" masks, which had an extra protective layer incorporated, as well as an eye splashguard built in at the
    top. Mask changes were mandated at least every 30 minutes, due to moisture build up. There was no official mask fit testing done, but we were trained nevertheless.
    In contrast, at present ear-loop surgical masks are the most widely available type for sale in Perth (Aust.) retail pharmacies. KN95 (uncertified) masks are available at the local hardware store.
    The Pharmaceutical Society of Australia several months ago published their professional journal "Australian Pharmacist with a front cover photo of a young lady in a very poorly fitting ear-loop surgical mask. There were wide gaps at the side and it did not even fit properly across the bridge of the nose. It should have been captioned "How not to wear a mask."
    My daughter gave ma a pack of ear-loop masks as a present. I experimented with them and found that attaching a rigid aluminium nose strip (available online) vertically down both sides almost eliminated the gap at the sides, giving a much better fit, though not as good as a shaped N95 mask.
    We have not had any community transmission of COVID-19 recorded in my state for many weeks, but I still wear a N95 mask on public transport. An amateur fit test can be done by holding a very thin piece of paper a couple of centimetres from the upper or side borders of your mask & watching for paper movement when you breathe. If you wear spectacles and they fog up when you wear a mask, that's a telltale sign too.
    CONFLICT OF INTEREST: None Reported
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    Well Known Ear Loops Don't Have Good Fitting Characteristics
    Roy McKay, Ph.D. | University of Cincinnati
    It's well known ear loops don't offer good fitting characteristics. This is one reason why NIOSH does not accept facepieces with ear loops for N95 filtering facepiece respirator certification. Vertical fold KN95 respirators without NIOSH-approval that come in only one size will also have problems passing a fit test. When reviewing studies it's important to recognize that fit (or lack of) will likely cause far more leakage than filter penetration. Furthermore, the fitting characteristics of NIOSH-approved N95 filtering facepiece respirators (FFR) can also vary significantly. The fitting characteristics of N95 FFRs is not evaluated as part of the current NIOSH certification process. Those of us who have been fitting FFRs for several decades were well aware of this and steer away from poorly designed facepieces. ASTM recently published a standard method (F3407-20) for evaluating respirator fit capability for half facepiece respirators including FFRs. If NIOSH adopts this ASTM method, or something similar, respirators with poor fitting characteristics will not pass. There are no real surprises here. Unfortunately, healthcare has been slow to understand respiratory protection.
    CONFLICT OF INTEREST: None Reported
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