Some research to 'get you started'

The following is a list of links in connection with the wearing of masks. Please do your own research!!!

Remember Chris Witty, Chief Medical Officer in The Independent in March?

https://www.independent.co.uk/news/uk/home-news/coronavirus-uk-news-professor-chris-whitty-no-masks-advice-a9374086.html

​For those who think wearing cloth masks in public is a good idea, or "better than nothing," please read.

Mask wearing drop 🏼

"This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection. Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for HCWs, particularly in high-risk situations, and guidelines need to be updated.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4420971/#__ffn_sectitle

https://bmjopen.bmj.com/content/5/4/e006577.full

https://www.cidrap.umn.edu/news-perspective/2020/04/data-do-not-back-cloth-masks-limit-covid-19-experts-say

Cloth masks can increase infection

https://www.who.int/publications-detail/advice-on-the-use-of-masks-in-the-community-during-home-care-and-in-healthcare-settings-in-the-context-of-the-novel-coronavirus-(2019-ncov)-outbreak

From the WHO: There is limited evidence that wearing a medical mask by healthy individuals in the households or among contacts of a sick patient, or among attendees of mass gatherings may be beneficial as a preventive measure.14-23 However, there is currently no evidence that wearing a mask (whether medical or other types) by healthy persons in the wider community setting, including universal community masking, can prevent them from infection with respiratory viruses, including COVID-19.

Masks-

Prolonged wearing of the surgical mask causes loss of intellect potential and cognitive performance due to a decrease in blood oxygen and subsequent brain hypoxia. Note - some changes may be irreversible.

"Report on surgical mask induced deoxygenation during major surgery" https://www.ncbi.nlm.nih.gov/pubmed/18500410

"Seventy percent of the patients showed a reduction in partial pressure of oxygen (PaO2), and 19% developed various degrees of hypoxemia. Wearing an N95 mask significantly reduced the PaO2 level"

https://www.ncbi.nlm.nih.gov/pubmed/15340662

"Wearing N95 masks results in hypooxygenemia and hypercapnia which reduce working efficiency and the ability to make correct decision."

...

"Medical staff are at increased risk of getting 'Severe acute respiratory syndrome' (SARS), and wearing N95 masks is highly recommended by experts worldwide. However, dizziness, headache, and short of breath are commonly experienced by the medical staff wearing N95 masks. The ability to make correct decision may be hampered, too."

https://clinicaltrials.gov/ct2/show/NCT00173017

https://www.researchgate.net/…/7332926_Headaches_and_the_N9…

"Chronic hypoxia-hypercapnia influences cognitive function"

https://www.ncbi.nlm.nih.gov/pubmed/18331781

"Hypercapnia status has been shown to predict mild cognitive impairment https://www.nature.com/articles/s41598-018-35797-3

Chronic hypoxia – hypercapnia has been seen as a cause of cognitive impairment https://www.atsjournals.org/…/fu…/10.1164/ajrccm.186.12.1307

https://www.ncbi.nlm.nih.gov/pubmed/31479137

https://www.ncbi.nlm.nih.gov/pubmed/26952529

https://bmjopen.bmj.com/content/5/4/e006577#T1

updated to find information on cloth mask particle filtration. I did also include a review from 1967 on all the studies about development of masks that is a fascinating read. It is important to read the whole thing if you start. If you just read the first page you will be differently informed than reading the whole thing (it's short!)

Fit testing matters less vs it’s an N95 mask: https://www.ncbi.nlm.nih.gov/pubmed/21477136

Masks don’t seem to impact family infection as much: https://www.ncbi.nlm.nih.gov/pubmed/28039289

Cloth masks not effective relative to normal medical masks: https://bmjopen.bmj.com/content/5/4/e006577.long

https://www.ncbi.nlm.nih.gov/pubmed/20584862

Gotta use the mask and do all the other things too: https://www.ncbi.nlm.nih.gov/pubmed/22188875

Medical or N95 isn’t that different: https://www.ncbi.nlm.nih.gov/pubmed/31479137

Cloth masks worse than surgical masks for anything <2.5 uM: https://www.ncbi.nlm.nih.gov/pubmed/27531371

What kills things on masks?

https://www.ncbi.nlm.nih.gov/pubmed/29855107: yes: bleach, UVC,autoclave, TERC no: UVA, alcohol

https://www.ncbi.nlm.nih.gov/pubmed/29678452: UVGI is a yes

https://www.ncbi.nlm.nih.gov/pubmed/25806411 UVGI works, and mask still good, but much more fragile (90% more)

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0186217

Can you breathe if you double mask?

https://www.ncbi.nlm.nih.gov/pubmed/23108786 : less well if it’s a surgical mask over an N95

We need more studies

https://www.ncbi.nlm.nih.gov/pubmed/25858901

This might be where we get the guidance from:

https://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=s04272006

_______________________________________

2020. Lancet. We have no uniform policy:

https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(20)30134-X/fulltext

History of surgical masks: https://www.ncbi.nlm.nih.gov/pubmed/5333967

This paper was actually a great read. Basically walks up to the invention of plastic masks with filters. You can’t get a fabric mask wet, and it’s much less effective without a lining (in the citation they were using packed cotton as the best lining)

The take home wrt cloth masks stopping viral particles of ~120 nm or cough particles less than 1 um:

Distribution of particle sizes in a cough maxes out at ~9

Distribution of particle sizes in a cough maxes out at ~900 nm: https://bmcpulmmed.biomedcentral.com/articles/10.1186/1471-2466-12-11

Most particles under 1 um: Fabian P, Mcdevitt JJ, Dehaan WH et al. (2008) Influenza virus in human exhaled breath: an observational study.

Cloth masks not very efficient with small particles (in some cases negligible filtering):

https://bmjopen.bmj.com/content/5/4/e006577.full: Laboratory tests showed the penetration of particles through the cloth masks to be very high (97%) compared with medical masks (44%) (used in trial) and 3M 9320 N95 (<0.01%), 3M Vflex 9105 N95 (0.1%).

Highly recommend reading this one- particle size breakdown and fabric differences for cloth masks and particle penetration: https://doi.org/10.1093/annhyg/meq044

Cloth masks worse than surgical masks for anything <2.5 uM (** the one brand had a filter, and was the best performing cloth mask): https://www.ncbi.nlm.nih.gov/pubmed/27531371

_______________________________________________________

https://www.nature.com/articles/s41591-020-0843-2

In conclusion, both surgical and cotton masks seem to be ineffective in preventing the dissemination of SARS–CoV-2 from the coughs of patients with COVID-19 to the environment and external mask surface.

https://annals.org/aim/fullarticle/2764367/effectiveness-surgical-cotton-masks-blocking-sars-cov-2-controlled-comparison

Mask wearing can increase infection. Most people do not even know how to wear or use them.

https://www.news-medical.net/news/20200315/Wearing-masks-may-increase-your-risk-of-coronavirus-infection-expert-says.aspx

US surgeon general warns against wearing face coverings.

https://www.businessinsider.com/americans-dont-need-masks-pence-says-as-demand-increases-2020-2

AND... one more. We need science before mandates.

https://www.drbrownstein.com/we-must-wear-face-masks-show-me-the-science-behind-that/?fbclid=iwar38czap444d14oxh9lq_oz-r8acwn-zoexkpu558tvy8npskv9owcg8gsi

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