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A cluster randomised trial of cloth masks compared with medical masks in healthcare workers
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  • Published on:
    Effectiveness of Cloth Mask in Health care workers
    • Clint'Niqua R Johnson, Nursing Student University of the Bahamas
    • Other Contributors:
      • Dr. Terry Campbell, Lecturer

    Dear Editors:
    This response is in relation to the captioned above article published in April 2015. Firstly, I would like to commend you guys on a job well done in this trial. Also, I would like to state that this was a very interesting, critical, and timely study of what’s going on in the world. As I begin to read this article, I immediately realized with no doubt the biasness of cloth masks in health care workers explained in this article. However, 2020 has been a year where a global pandemic has tragically affected many healthcare systems. Hence, causing shortages of PPE for healthcare workers. I must agree with some responses made that cloth mask should have been presented as less effective and not high risk in health care workers. Also, to the bias results of cloth mask, there should have been the identification on the types of materials which can be used and not used for the cloth mask.
    It is quite evident that health care workers cannot work this pandemic without protection, however, if there is a shortage of surgical mask what is the next option provided. In the article you state, “compliance was significantly higher in the cloth mask….” (Macintyre et al., 2015) therefore this should be evidence that health care workers have no problem with wearing cloth masks. Conversely, a recommendation if healthcare workers are allowed to wear mask, there should be a place where they can find the filters used inside the surgical mask to be placed in a cloth mask. Th...

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    Conflict of Interest:
    None declared.
  • Published on:
    Re: A cluster randomised trial of cloth masks compared with medical masks in healthcare workers
    • Montana S. Lightbourne, Nursing Student University of The Bahamas
    • Other Contributors:
      • Dr. Terry Campbell, Nursing Lecturer

    Dear Editor,
    This response is concerning the captioned article above published on April 22, 2015. First of all, I would like to regard how the editorial is informative and insightful, as I've appreciated the study. I started to gain a precise understanding of the primary subject of concern when reading the article. Although assessing the productiveness of cloth masks when operating in high-risk hospital wards and whether they are especially useful compared to surgical masks in preventing the transmission of respiratory infections is something that we should most certainly think about but, it then raises the question, which one of these masks provides the best protection from COVID-19 (SARS-CoV-2), given as it is now 2020 and we are currently in a worldwide pandemic?
    In contrast to a medical mask, this study provided insight only on the detrimental consequences for the use of a cloth mask for healthcare workers, such as results showing that they have the highest incidence of all infection outcomes, but the use of face covers or masks should not be restricted as there is evidence from researchers that its use can help prevent the spread of infection. The majority of virus transmission occurs in bodily fluids from larger particles, either aerosol or droplets, which are directly generated by talking, chewing, coughing, and sneezing. Droplets and aerosols can be blocked by fabric, and layers of this cloth fabric add effectiveness. (Clase et al., 2020).
    Re...

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    Conflict of Interest:
    None declared.
  • Published on:
    Application To Covid-19

    Cloth masks, while comforting to some, should not be implied to provide anything but marginal (at best) protection to this "epidemic". When referring to virus particles that can spread via droplets it is fairly apparent that cloth masks do little to nothing for protection (except piece of mine)...and sorry, but 3ish% is not even a nominal value, its a toss value when referring to health.

    Take a covid 19 positive patient, have them where a cloth mask and exhale sharply, sneeze, or cough in front of a mirror....watch what happens. I understand this is an overly simplified example, but it gets the point across.

    As a last ditch effort with nothing else? Sure, but as a primary line of active defense for at risk individuals? Not even close. These individuals should be protected, away from the "herd" community.

    Conflict of Interest:
    None declared.
  • Published on:
    This article DOES NOT apply to COVID-19/SARS-CoV2

    When 85% of the viruses found in laboratory tests were rhinoviruses, which are about four times smaller than SARS-CoV2, no conclusion from this article can be applied to COVID-19/SARS-CoV2. No coronaviruses of any kind were found even though the tests were performed. Finally, their claim that "Penetration of cloth masks by particles was almost 97%" is of no value when the particles sizes are not stated. Furthermore, since many viruses, such as influenza, herpes simplex, and coronaviruses are surrounded by a fatty layer, called a "lipid envelope," one wonders about the choice of sodium chloride particles instead of oil particles, taking in consideration that the instrument used (TSI 8110 Filter tester) can use either.

    Conflict of Interest:
    None declared.
  • Published on:
    It is important to consider the size and incident flow rate of particles tested here compare with the size and typical incident flow rate of respiratory droplets?
    • Daniel W Sazer, Graduate student researcher Rice University Department of Bioengineering

    Very nice work by the authors. Perhaps they could provide additional details about the methods used here to test particle filtration.

    Conflict of Interest:
    None declared.
  • Published on:
    A cluster randomised trial of cloth masks compared with medical masks in healthcare workers

    The suggestion that cloth masks can lead to increased infection compared to no mask is not substantiated The control arm had less than 1% of no mask use and therefore the statement is an assumption not a proof . It could be possible for bacteria or fungi that could multiply on the mask but for virus it would have to shown there is more bioavailability than no mask .

    Conflict of Interest:
    None declared.
  • Published on:
    Vicki Macleod

    The authors do not state what kind / standard of cloth masks were used. Is there any chance they could do this. Given the huge shortage of FFP2 and FFP3 masks, it would be helpful to know the authors’ views of advice from the CDC in the US. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth...

    Conflict of Interest:
    None declared.
  • Published on:
    Microbiologist & Regional Industrial Hygienist
    • Jorge K. Leong, Biological scientist U.S. Occupational Health & Safety Administration (former employer)

    I like the article. However, in my humble opinion, I wish there is a Material section in it describing the different types of fabrics the masks are made of. If circumstances do not permit detail descriptions of individual masks, it would generate more scientific value if the materials can be grouped and categorized, at least broadly, such as solid cotton sheet, gauze, etc. Similarly, statements, on the number of fabric layers in and photographs of the different shapes of representative groups of masks would be very useful.

    Conflict of Interest:
    None declared.
  • Published on:
    Cloth masks for general population

    Thank you for your work. It seems that in addition to healthcare workers, many people in the general population are referring to your research about cloth masks for guidance about homemade ("DIY")masks for use in the general population. If you are able to provide an addendum to your original research similar to this one addressing the question of their suitability for the general population that would be very helpful.

    Conflict of Interest:
    None declared.
  • Published on:
    Why not interpret the cloth masks as being less protective rather than presenting high risk?

    This is a critical study, being the only C-RCT to evaluate cloth masks, and it will carry inordinate weight until more studies are done. It makes findings and recommendations which have pretty drastic implications and gainsay widespread practice. It therefore is appropriate, I think to test it with some devil's advocate interrogation. I wish to raise 3 such arguments that I hope will generate debate.

    1. The 2015 study shows that the cloth masks have higher rates of infection in the health workers (RR 1.51 for CRI, 1.72 for for lab confirmed infection). Actual infection rates were 7.6% versus 4.8%. But as the authors have stated, there was no no-mask control group. To quote the authors "The finding of a much higher rate of infection in the cloth mask arm could be interpreted as harm caused by cloth masks, efficacy of medical masks, or most likely a combination of both.” But why not draw the conclusion that the cloth masks are simply less effective at reducing infection.

    For example, some studies indicate medical masks are highly effective – assume an 80% reduction of infection, for both N95 and surgical masks. If, say, out of 100 infections that would have occurred, medical masks prevented 80, resulting in 20 infections, and according to this study, cloth masks would result in 51% more (RR=1.51), i.e. 30 cases, or at upper limit of 95%CI, RR=2.49 i.e. 50 cases, then the cloth masks have still avoided between 50 and 70 cases, i.e. more than half...

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    Conflict of Interest:
    None declared.
  • Published on:
    COVID-19, shortages of masks and the use of cloth masks as a last resort
    • Chandini R MacIntyre, Academic physician The Kirby Institute, University of New South Wales
    • Other Contributors:
      • Chi Dung Tham, Academic physician
      • Holly Seale, Academic
      • Abrar Chughtai, Academic physician

    Critical shortages of personal protective equipment (PPE) have resulted in the US Centers for Disease Control downgrading their recommendations for health workers treating COVID-19 patients from respirators to surgical masks and finally to home-made cloth masks. As authors of the only published randomised controlled clinical trial of cloth masks, we have been getting daily emails about this from health workers concerned about using cloth masks. The study found that cloth mask wearers had higher rates of infection than even the standard practice control group of health workers, and the filtration provided by cloth masks was poor compared to surgical masks. At the time of the study, there had been very little work done in this space, and so little thought into how to improve the protective value of the cloth masks. Until now, most guidelines on PPE did not even mention cloth masks, despite many health workers in Asia using them.

    Health workers are asking us if they should wear no mask at all if cloth masks are the only option. Our research does not condone health workers working unprotected. We recommend that health workers should not work during the COVID-19 pandemic without respiratory protection as a matter of work health and safety. In addition, if health workers get infected, high rates of staff absenteeism from illness may also affect health system capacity to respond. Some health workers may still choose to work in inadequate PPE. In this case, the physic...

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    Conflict of Interest:
    We were the authors of the 2015 RCT , which was funded by an Australian Research Council Linkage Grant with 3M as the partner on the grant.