4 ms·
Because it's unconstitutional and masks don't even work unless they are N95 which are fitted. Neither for the wearer, nor for the people around them. https://w
by blisseyGo 6y ago
Because it's unconstitutional and masks don't even work unless they are N95 which are fitted. Neither for the wearer, nor for the people around them.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7181938/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7181938/
https://www.cdc.gov/eid/article/26/5/19-0994_article https://www.cdc.gov/eid/article/26/5/19-0994_article
> Disposable medical masks (also known as surgical masks) are loose-fitting devices that were designed to be worn by medical personnel to protect accidental contamination of patient wounds, and to protect the wearer against splashes or sprays of bodily fluids (36). There is limited evidence for their effectiveness in preventing influenza virus transmission either when worn by the infected person for source control or when worn by uninfected persons to reduce exposure. Our systematic review found no significant effect of face masks on transmission of laboratory-confirmed influenza.
> We did not consider the use of respirators in the community. Respirators are tight-fitting masks that can protect the wearer from fine particles (37) and should provide better protection against influenza virus exposures when properly worn because of higher filtration efficiency. However, respirators, such as N95 and P2 masks, work best when they are fit-tested, and these masks will be in limited supply during the next pandemic. These specialist devices should be reserved for use in healthcare settings or in special subpopulations such as immunocompromised persons in the community, first responders, and those performing other critical community functions, as supplies permit.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4420971/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4420971/
> Penetration of cloth masks by particles was almost 97% and medical masks 44%. 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.osha.gov/Publications/OSHA3767.pdf https://www.osha.gov/Publications/OSHA3767.pdf
> The purpose of a facemask, when worn by a patient suspected or confirmed with an illness such as influenza or tuberculosis, is to reduce the amount of large infectious particles released as the patient talks, sneezes, or coughs; this limits their concentration in the room air and reduces the infection risk to others who are present.
> However, facemasks by design do not seal tightly to the wearer’s face. Therefore, they allow unfiltered air to easily flow around the sides of the facemask into the breathing zone and respiratory tract of the wearer. In addition, the materials used for facemasks are not regulated for their ability to filter particles and are known to vary greatly between models. This makes it possible for small particles to pass through or around the facemask and be inhaled by the wearer. This is why they are not considered respiratory protection— facemasks do NOT provide the wearer with a reliable level of protection from inhaling smaller particles, including those emitted into the room air by a patient who is exhaling or coughing, or generated during certain medical procedures.
Also eyes are an entry point too:
https://www.biorxiv.org/content/10.1101/2020.05.09.086165v1.full https://www.biorxiv.org/content/10.1101/2020.05.09.086165v1....
> Conclusions: Together, these results indicate that ocular surface cells including conjunctiva are susceptible to infection by SARS-CoV-2, and could therefore serve as a portal of entry as well as a reservoir for person-to-person transmission of this virus. This highlights the importance of safety practices including face masks and ocular contact precautions in preventing the spread of COVID-19 disease.
EDIT: Why is everyone downvoting me? I literally shared multiple studies which state "There is limited evidence for their effectiveness in preventing influenza virus transmission either when worn by the infected person for source control or when worn by uninfected persons to reduce exposure."
- perl4ever 6y ago>I literally shared multiple studies which state "There is limited evidence for their effectiveness in preventing influenza virus transmission either when worn by the infected person for source control or when worn by uninfected persons to reduce exposure." It's the first half that I would take issue with, and I don't see anything you quoted as convincingly supporting it. Garden variety masks are not suitable for healthcare professionals; that's why N95 masks are reserved for them. But the ordinary masks are vital to reduce the odds of transmission where the proportions of infected to not-infected are inverted. It's fundamentally different whether you have one (potentially) infected person surrounded by non-infected people, or one (presumably) non-infected person surrounded by infected people. The latter needs an N95 and maybe more, and the former needs anything as long as it deflects exhalations a little.
- blisseyGo 6y agoAs I mentioned to the other person, the first study I cited states: > There is limited evidence for their effectiveness in preventing influenza virus transmission either when worn by the infected person for source control or when worn by uninfected persons to reduce exposure. The later study also states non-N95 masks allow 97%. So basically useless.
- perl4ever 6y agoI don't see the statement that there is "limited evidence" for something as providing information. Is there "unlimited evidence" for anything?
- yodon 6y agoThe studies you cite focus on the use of masks to protect the wearer of the mask. The purpose of masks is not to protect the wearer of the mask but to protect others. In simple hand-waving terms the mask diffuses the wearer's exhalation reducing the velocity of the air stream and its contained particles, thereby reducing the distance the particles can travel and increasing the odds that the particles drop out of the airstream and onto a surface before they encounter another person. The diffusive effects of masks does not provide a 100% barrier but given that Covid-19 appears to be predominantly transmitted via airborne particles rather than surface contact, mask wearing can still have a large impact on transmission without being directly protective of the wearer.