3 ms·

You are spreading false information. Reusable masks do "work." Masks lose effectiveness over time and should be changed regularly, but it is not true that "corr

You are spreading false information. Reusable masks do "work." Masks lose effectiveness over time and should be changed regularly, but it is not true that "correct" usage involves changing them "numerous times a day." There are two major factors that, as I understand it, drive the use of disposable masks in clinical settings. First is that healthcare workers see many sick people a day and they are worried about surface transmission. This is the main reason why they need to change their masks so often. The rest of us, who are moving through the world without looking directly into the mouths of sick people, have fewer foreign moisture on our masks. The second is that masks do become less effective over time, but the relative import of mask effectiveness should be judged proportionally to risk of the situation. Again, clinical workers are in a higher risk situation, so they change masks more often. The utility for the general public is lower. Cloth masks were called into question early in the pandemic due to a 2015 study indicating they spread disease[1]. This was in a medical setting and, as I understand it (I am a layman) it was because of poor mask sanitation (i.e. using masks for many days without cleaning). My understanding is that using a cloth mask for a day is better than no mask. Of course it would be better to change it more often, but the relative risk is low. Since then we have done a number of studies on cloth masks in the population and those studies have shown that cloth masks are effective[2]. It is true that "better" masks protect better, but that protection is almost always trumped by compliance. The mask you will wear is 100% better than the mask you won't wear. So health experts have focused on that. The medical community has done a shit job of communicating this, but that's no reason to say things that don't seem to be true. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4420971/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4420971/ [2] https://www.ucsf.edu/news/2020/06/417906/still-confused-about-masks-heres-science-behind-how-face-masks-prevent https://www.ucsf.edu/news/2020/06/417906/still-confused-abou...

EB-Barrington 6y ago
No matter which of those two mask types are employed, a relevant May 2020 meta-study on pandemic influenza published by the CDC found that face masks had no effect, neither as personal protective equipment nor as a source control. "In pooled analysis, we found no significant reduction in influenza transmission with the use of face masks". "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." "Proper use of face masks is essential because improper use might increase the risk for transmission." Has the CDC analysis been refuted? https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article
- dragonwriter 6y ago
  > May 2020 meta-study on pandemic influenza That's probably quite important if you are trying to control pandemic influenza, but SARS-COV-2 isn't influenza. Different pathogens have different characteristics, and thus different responses to protective measures. AFAIK, most influenzas are much more prone to airborne transmission than SARS-COV-2, where the main concern is droplet transmission (though some airborne transmission seems to occur), against which masks that are ineffective against airborne transmission can be quite effective. You wouldn't judge the value of condoms in preventing the spread of AIDS by studies of how effective they were in preventing the spread of the flu, either.
  - EB-Barrington 6y ago
    What size particle/droplet is most important in stopping Covid transmission?
- jcheng 6y ago
  https://www.cdc.gov/coronavirus/2019-ncov/more/masking-science-sars-cov2.html https://www.cdc.gov/coronavirus/2019-ncov/more/masking-scien... https://www.nature.com/articles/d41586-020-02801-8 https://www.nature.com/articles/d41586-020-02801-8
- aeturnum 6y ago
  As I said, I'm a layman, but several things jump out to me. The first thing I think of is that the meta-study you linked is for influenza. Obviously covid and influenza are similar but I think there are important differences (we did not, for instance, have as many cases of influenza in any of the last fifty years as we have of covid this year). In particular, I know that the asymptomatic transmission of covid is unusual and is not something that happens in influenza[0]. The studies that support mask wearing in my link are on mask mandates (though there are also case studies that suggest masks have been effective). I believe that mandating masks reduces transmission of the virus and I don't think it's necessary to reconcile that fact with the fact that masks don't reduce the spread of influenza. The version of the study you linked is formatted oddly and the tables are on another page. A pdf of their article is easier to read, I think [3]. From Table 2 (and the discussion around it) I take that they are hoping to catalog open questions and are not seeking to make a recommendation about proper procedure. Therefore I think it's perfectly in keeping with Jingyi Xiao, et. al. to recommend wearing masks based on the covid-specific studies while recognizing we have no evidence that masks prevent influenza. [0] While you can transmit influenza when you're not showing symptoms, my understanding is that covid is different enough that we shouldn't compare them. That could be wrong and if you have anything to contribute I'd be interested to see it. [1] https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818 https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818 [2] https://www.researchgate.net/publication/342198360_Association_of_country-wide_coronavirus_mortality_with_demographics_testing_lockdowns_and_public_wearing_of_masks_Update_June_15_2020 https://www.researchgate.net/publication/342198360_Associati...
nickthemagicman 6y ago
I coul get into the epidemiology and biology of a pathogen that stays on surfaces for days. But for simplicity sake I'll just say this. I wouldn't want my surgeon walking in to give me surgery, with a mask he just used from another operation. Corona virus doesn't become any less deadly or contagious outside of a medical institution. Also falsely accusing someone of spreading false information Should be like falsely accusing someone of rape. The accuser should go to jail or get banned if they're wrong.
- aeturnum 6y ago
  Exactly, which is why I pointed out that healthcare workers frequently change masks for reasons related to their environment. It's also, of course, why medical workers wore surgical masks before covid. PPE worn outside of clinical settings already exist in a lower risk situation and so it's reasonable to accept lower standards for it.
  - nickthemagicman 6y ago
    Lower standards? You mean standards like applying a device directly onto your respiratory system that's been potentially exposed for long periods of time to a virus that stays on surfaces for days? These aren't lower standards these are freaking negative standards. The virus doesn't become less deadly or less contagious outside of medical institutions.
deleted 6y ago
[deleted]

EB-Barrington 6y ago

No matter which of those two mask types are employed, a relevant May 2020 meta-study on pandemic influenza published by the CDC found that face masks had no effect, neither as personal protective equipment nor as a source control. "In pooled analysis, we found no significant reduction in influenza transmission with the use of face masks". "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." "Proper use of face masks is essential because improper use might increase the risk for transmission." Has the CDC analysis been refuted? https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article https://wwwnc.cdc.gov/eid/article/26/5/19-0994_article

dragonwriter 6y ago
> May 2020 meta-study on pandemic influenza That's probably quite important if you are trying to control pandemic influenza, but SARS-COV-2 isn't influenza. Different pathogens have different characteristics, and thus different responses to protective measures. AFAIK, most influenzas are much more prone to airborne transmission than SARS-COV-2, where the main concern is droplet transmission (though some airborne transmission seems to occur), against which masks that are ineffective against airborne transmission can be quite effective. You wouldn't judge the value of condoms in preventing the spread of AIDS by studies of how effective they were in preventing the spread of the flu, either.
- EB-Barrington 6y ago
  What size particle/droplet is most important in stopping Covid transmission?
jcheng 6y ago
https://www.cdc.gov/coronavirus/2019-ncov/more/masking-science-sars-cov2.html https://www.cdc.gov/coronavirus/2019-ncov/more/masking-scien... https://www.nature.com/articles/d41586-020-02801-8 https://www.nature.com/articles/d41586-020-02801-8
aeturnum 6y ago
As I said, I'm a layman, but several things jump out to me. The first thing I think of is that the meta-study you linked is for influenza. Obviously covid and influenza are similar but I think there are important differences (we did not, for instance, have as many cases of influenza in any of the last fifty years as we have of covid this year). In particular, I know that the asymptomatic transmission of covid is unusual and is not something that happens in influenza[0]. The studies that support mask wearing in my link are on mask mandates (though there are also case studies that suggest masks have been effective). I believe that mandating masks reduces transmission of the virus and I don't think it's necessary to reconcile that fact with the fact that masks don't reduce the spread of influenza. The version of the study you linked is formatted oddly and the tables are on another page. A pdf of their article is easier to read, I think [3]. From Table 2 (and the discussion around it) I take that they are hoping to catalog open questions and are not seeking to make a recommendation about proper procedure. Therefore I think it's perfectly in keeping with Jingyi Xiao, et. al. to recommend wearing masks based on the covid-specific studies while recognizing we have no evidence that masks prevent influenza. [0] While you can transmit influenza when you're not showing symptoms, my understanding is that covid is different enough that we shouldn't compare them. That could be wrong and if you have anything to contribute I'd be interested to see it. [1] https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818 https://www.healthaffairs.org/doi/10.1377/hlthaff.2020.00818 [2] https://www.researchgate.net/publication/342198360_Association_of_country-wide_coronavirus_mortality_with_demographics_testing_lockdowns_and_public_wearing_of_masks_Update_June_15_2020 https://www.researchgate.net/publication/342198360_Associati...

nickthemagicman 6y ago

I coul get into the epidemiology and biology of a pathogen that stays on surfaces for days. But for simplicity sake I'll just say this. I wouldn't want my surgeon walking in to give me surgery, with a mask he just used from another operation. Corona virus doesn't become any less deadly or contagious outside of a medical institution. Also falsely accusing someone of spreading false information Should be like falsely accusing someone of rape. The accuser should go to jail or get banned if they're wrong.

aeturnum 6y ago
Exactly, which is why I pointed out that healthcare workers frequently change masks for reasons related to their environment. It's also, of course, why medical workers wore surgical masks before covid. PPE worn outside of clinical settings already exist in a lower risk situation and so it's reasonable to accept lower standards for it.
- nickthemagicman 6y ago
  Lower standards? You mean standards like applying a device directly onto your respiratory system that's been potentially exposed for long periods of time to a virus that stays on surfaces for days? These aren't lower standards these are freaking negative standards. The virus doesn't become less deadly or less contagious outside of medical institutions.

deleted 6y ago

[deleted]