4 ms·

does wearing a mask stop from spreading if you have it or stop you from getting it from others or both?

by MuffinFlavored 4y ago

Baeocystin 4y ago
An N95 does both, to a highly effective degree.
- deleted 4y ago
  [deleted]
- timr 4y ago
  We have no good evidence for this claim. The only studies involving n95 masks and respiratory illness were conducted in hospital settings (i.e. don't reflect "normal" life), have high risk of bias (i.e. were small and were not randomized, controlled trials), and have shown mixed results. This is the WHO review that summarized the existing evidence for masks at the start of the pandemic. There were 4 studies on n95 masks in hospitals: https://www.thelancet.com/journals/lancet/article/PIIS0140-6 https://www.thelancet.com/journals/lancet/article/PIIS0140-6... Additionally, this is the most comprehensive review of mask literature I am aware of. It explicitly states that: > At least ten studies evaluate the clinical efficacy of different types of masks compared to one another, but without a no-mask control group most provide little insight into mask efficacy. > Four RCTs, four meta-analyses, and one prospective cohort study found surgical masks were non-inferior to N95s for protection against respiratory infections, and one found evidence that N95s provide greater protection than medical masks against self-reported clinical respiratory illness but not ILI. However, a recent review found that evidence that N95s protect healthcare workers from clinical respiratory infections at all is “low quality". One meta-analysis of particular note, an April 2020 preprint of a Cochrane review of clinical evidence for both surgical and N95 masks, “did not find any differences in the clinical effectiveness of either type of mask in the setting of respiratory viral infection transmission to healthcare workers,” although the review’s final November version omitted this language. https://www.cato.org/sites/cato.org/files/2021-11/working-paper-64.pdf https://www.cato.org/sites/cato.org/files/2021-11/working-pa... We simply don't know if n95 masks provide any protection -- personal or otherwise -- in the real world. That is the only honest answer to the parent's question. Everyone who claims otherwise is extrapolating from laboratory experiments, low-quality observational data, or (this is probably the most common) hearsay.
  - HyperSane 4y ago
    Why do surgeons wear masks?
    - MobiusHorizons 4y ago
      Not an expert, but as I understand it, surgeons could be exposed to much more than airborne viruses (bacteria, bodily fluids, etc). So masks would be worn for more possible reasons. It’s a good question though, I hope someone knowledgeable answers it.
      - azakai 4y ago
        Surgical masks and face shields are indeed designed specifically to protect from fluids. That is very important too. Separately from that, when there is a risk of airborne transmission as there is with Covid, doctors and nurses will wear appropriate masks like N95s.
  - andbberger 4y ago
    nonsense, N95s are highly effective and if you want to make a good faith argument that they're not try citing the new england journal of medicine and not the fucking cato institute, good lord
    - deleted 4y ago
      [deleted]
  - azakai 4y ago
    > We simply don't know if n95 masks provide any protection -- personal or otherwise -- in the real world. That is simply not true. First, doctors and researchers consistently say that N95s are known to provide protection against Covid. Second, this is the first google result on that topic: https://www.cdc.gov/mmwr/volumes/71/wr/mm7106e1.htm https://www.cdc.gov/mmwr/volumes/71/wr/mm7106e1.htm Quoting from that CDC page: > What is already known about this topic? > Face masks or respirators (N95/KN95s) effectively filter virus-sized particles in laboratory settings. The real-world effectiveness of face coverings to prevent acquisition of SARS-CoV-2 infection has not been widely studied. > What is added by this report? > Consistent use of a face mask or respirator in indoor public settings was associated with lower odds of a positive SARS-CoV-2 test result (adjusted odds ratio = 0.44). Use of respirators with higher filtration capacity was associated with the most protection, compared with no mask use. > What are the implications for public health practice? > In addition to being up to date with recommended COVID-19 vaccinations, consistently wearing a comfortable, well-fitting face mask or respirator in indoor public settings protects against acquisition of SARS-CoV-2 infection; a respirator offers the best protection. You can say that that might be just correlation, but as those quotes mention, we do know how N95s work: they filter viral particles. That is easy to prove in lab settings. Real-world settings involve more factors, like how well-fitting the mask is, but it would be very surprising if a good N95 properly used did not offer any protection! N95 masks work. It's a good idea to wear one when relevant.
VancouverMan 4y ago
Some long-term, large-scale studies of the effects of widespread public masking have been performed recently. For example, one lasting over 1.5 years was done in the province of Ontario, Canada, involving approximately 15,000,000 participants, in environments ranging from dense urban settings to sparse rural ones. In Ontario's largest and densest population center, Toronto, the duration this study was about 2 years in length. It was conclusively demonstrated that widespread public masking does not prevent infection, and it does not prevent transmission, of airborne viruses. It was conclusively proven that such masking did cause accessibility problems, it did cause significant social disruption, and it did cause environmental damage, among numerous other harmful effects.
- HyperSane 4y ago
  Can you provide a link to this study? If masks don't work then why do surgeons wear them?
  - samatman 4y ago
    To the latter question, it's to prevent droplets of spittle from landing on exposed tissue. There are pathogens which spread by droplets, rather than aerosols, the Sars2 virus doesn't happen to be one of them. Yes, if you spit directly onto an open wound or mucous tissue, but it doesn't live long on surfaces, and the droplet-fomite route is how that vector of infection works.
    - HyperSane 4y ago
      "prevent droplets of spittle from landing on exposed tissue" Isn't tiny droplets of saliva how most respiratory viruses spread?
  - lucb1e 4y ago
    They're joking that there were infections in the city despite mask requirements (surprise) and that mask requirements caused "significant social disruption".... At least I hope it's supposed to be a joke.

does wearing a mask stop from spreading if you have it or stop you from getting it from others or both?

Baeocystin 4y ago

An N95 does both, to a highly effective degree.

deleted 4y ago
[deleted]
timr 4y ago
We have no good evidence for this claim. The only studies involving n95 masks and respiratory illness were conducted in hospital settings (i.e. don't reflect "normal" life), have high risk of bias (i.e. were small and were not randomized, controlled trials), and have shown mixed results. This is the WHO review that summarized the existing evidence for masks at the start of the pandemic. There were 4 studies on n95 masks in hospitals: https://www.thelancet.com/journals/lancet/article/PIIS0140-6 https://www.thelancet.com/journals/lancet/article/PIIS0140-6... Additionally, this is the most comprehensive review of mask literature I am aware of. It explicitly states that: > At least ten studies evaluate the clinical efficacy of different types of masks compared to one another, but without a no-mask control group most provide little insight into mask efficacy. > Four RCTs, four meta-analyses, and one prospective cohort study found surgical masks were non-inferior to N95s for protection against respiratory infections, and one found evidence that N95s provide greater protection than medical masks against self-reported clinical respiratory illness but not ILI. However, a recent review found that evidence that N95s protect healthcare workers from clinical respiratory infections at all is “low quality". One meta-analysis of particular note, an April 2020 preprint of a Cochrane review of clinical evidence for both surgical and N95 masks, “did not find any differences in the clinical effectiveness of either type of mask in the setting of respiratory viral infection transmission to healthcare workers,” although the review’s final November version omitted this language. https://www.cato.org/sites/cato.org/files/2021-11/working-paper-64.pdf https://www.cato.org/sites/cato.org/files/2021-11/working-pa... We simply don't know if n95 masks provide any protection -- personal or otherwise -- in the real world. That is the only honest answer to the parent's question. Everyone who claims otherwise is extrapolating from laboratory experiments, low-quality observational data, or (this is probably the most common) hearsay.
- HyperSane 4y ago
  Why do surgeons wear masks?
  - MobiusHorizons 4y ago
    Not an expert, but as I understand it, surgeons could be exposed to much more than airborne viruses (bacteria, bodily fluids, etc). So masks would be worn for more possible reasons. It’s a good question though, I hope someone knowledgeable answers it.
    - azakai 4y ago
      Surgical masks and face shields are indeed designed specifically to protect from fluids. That is very important too. Separately from that, when there is a risk of airborne transmission as there is with Covid, doctors and nurses will wear appropriate masks like N95s.
- andbberger 4y ago
  nonsense, N95s are highly effective and if you want to make a good faith argument that they're not try citing the new england journal of medicine and not the fucking cato institute, good lord
  - deleted 4y ago
    [deleted]
- azakai 4y ago
  > We simply don't know if n95 masks provide any protection -- personal or otherwise -- in the real world. That is simply not true. First, doctors and researchers consistently say that N95s are known to provide protection against Covid. Second, this is the first google result on that topic: https://www.cdc.gov/mmwr/volumes/71/wr/mm7106e1.htm https://www.cdc.gov/mmwr/volumes/71/wr/mm7106e1.htm Quoting from that CDC page: > What is already known about this topic? > Face masks or respirators (N95/KN95s) effectively filter virus-sized particles in laboratory settings. The real-world effectiveness of face coverings to prevent acquisition of SARS-CoV-2 infection has not been widely studied. > What is added by this report? > Consistent use of a face mask or respirator in indoor public settings was associated with lower odds of a positive SARS-CoV-2 test result (adjusted odds ratio = 0.44). Use of respirators with higher filtration capacity was associated with the most protection, compared with no mask use. > What are the implications for public health practice? > In addition to being up to date with recommended COVID-19 vaccinations, consistently wearing a comfortable, well-fitting face mask or respirator in indoor public settings protects against acquisition of SARS-CoV-2 infection; a respirator offers the best protection. You can say that that might be just correlation, but as those quotes mention, we do know how N95s work: they filter viral particles. That is easy to prove in lab settings. Real-world settings involve more factors, like how well-fitting the mask is, but it would be very surprising if a good N95 properly used did not offer any protection! N95 masks work. It's a good idea to wear one when relevant.

VancouverMan 4y ago

Some long-term, large-scale studies of the effects of widespread public masking have been performed recently. For example, one lasting over 1.5 years was done in the province of Ontario, Canada, involving approximately 15,000,000 participants, in environments ranging from dense urban settings to sparse rural ones. In Ontario's largest and densest population center, Toronto, the duration this study was about 2 years in length. It was conclusively demonstrated that widespread public masking does not prevent infection, and it does not prevent transmission, of airborne viruses. It was conclusively proven that such masking did cause accessibility problems, it did cause significant social disruption, and it did cause environmental damage, among numerous other harmful effects.

HyperSane 4y ago
Can you provide a link to this study? If masks don't work then why do surgeons wear them?
- samatman 4y ago
  To the latter question, it's to prevent droplets of spittle from landing on exposed tissue. There are pathogens which spread by droplets, rather than aerosols, the Sars2 virus doesn't happen to be one of them. Yes, if you spit directly onto an open wound or mucous tissue, but it doesn't live long on surfaces, and the droplet-fomite route is how that vector of infection works.
  - HyperSane 4y ago
    "prevent droplets of spittle from landing on exposed tissue" Isn't tiny droplets of saliva how most respiratory viruses spread?
- lucb1e 4y ago
  They're joking that there were infections in the city despite mask requirements (surprise) and that mask requirements caused "significant social disruption".... At least I hope it's supposed to be a joke.