Post by barb43 on Oct 13, 2020 4:24:23 GMT
Mask Facts - Assoc of American Physicians & Surgeons
aapsonline.org/mask-facts/
Here it is! In my opinion, these people are the experts. They have published the definitive word on the subject of wearing masks to avoid spreading COVID-19.
Studies that have been done are discussed in the article and many summaries are drawn. Here are a few of the items in the article:
There is much more information contained in this article. It's worth the read!
aapsonline.org/mask-facts/
Here it is! In my opinion, these people are the experts. They have published the definitive word on the subject of wearing masks to avoid spreading COVID-19.
Studies that have been done are discussed in the article and many summaries are drawn. Here are a few of the items in the article:
Public health authorities define a significant exposure to COVID-19 as face-to-face contact within 6 feet with a patient with symptomatic COVID-19 that is sustained for at least a few minutes (and some say more than 10 minutes or even 30 minutes).
The chance of catching COVID-19 from a passing interaction in a public space is therefore minimal.
The chance of catching COVID-19 from a passing interaction in a public space is therefore minimal.
Study measuring filter efficiency (2014, Korea)
Evaluated 44 masks, respirators, and other materials with similar methods and small aerosols (0.08 and 0.22 µm)
N95 FFR filter — >95% efficiency
Medical masks — 55% efficiency
General (cloth) masks — 38% efficiency
Handkerchiefs — 2% (one layer) to 13% (four layers) efficiency.
Evaluated 44 masks, respirators, and other materials with similar methods and small aerosols (0.08 and 0.22 µm)
N95 FFR filter — >95% efficiency
Medical masks — 55% efficiency
General (cloth) masks — 38% efficiency
Handkerchiefs — 2% (one layer) to 13% (four layers) efficiency.
*The first randomized controlled trial of cloth masks in health care workers (2015, Australia).
Penetration of:
Cloth masks by particles — 97%
Medical masks — 44%,
3M Vflex 9105 N95 — 0.1%
3M 9320 N95 — <0.01%
Cloth masks resulted in significantly higher rates of infection than medical masks, and also performed worse than the control arm some of whom may have worn masks.
The virus may survive on the surface of the face masks.
Self-contamination through repeated use and improper doffing is possible. A contaminated cloth mask may transfer pathogen from the mask to the bare hands of the wearer.
Moisture retention, reuse of cloth masks, and poor filtration may result in increased risk of infection.
Cloth masks should not be recommended for health care workers, particularly in high-risk situations.
Penetration of:
Cloth masks by particles — 97%
Medical masks — 44%,
3M Vflex 9105 N95 — 0.1%
3M 9320 N95 — <0.01%
Cloth masks resulted in significantly higher rates of infection than medical masks, and also performed worse than the control arm some of whom may have worn masks.
The virus may survive on the surface of the face masks.
Self-contamination through repeated use and improper doffing is possible. A contaminated cloth mask may transfer pathogen from the mask to the bare hands of the wearer.
Moisture retention, reuse of cloth masks, and poor filtration may result in increased risk of infection.
Cloth masks should not be recommended for health care workers, particularly in high-risk situations.
There is much more information contained in this article. It's worth the read!
