4 ms·

N95 respirators vs surgical masks against acute respiratory infection (2016)

34 points by luu 7y ago

yodon 7y ago
This is great news, particularly after seeing a huge fraction of N95 wearers in Northern California last summer wear the masks incorrectly in ways that made their presence useless.
- AstralStorm 7y ago
  What great news? They found mostly no difference in risk vs surgical masks...
  - yodon 7y ago
    Correct. Surgical masks help. N95 masks help exactly as much as surgical masks. Poorly worn N95 masks are equivalent to surgical masks, therefore poorly worn N95 masks help as much as properly worn N95 masks. The US is going to be full of people wearing N95 masks incorrectly. This paper says that's ok they are still protecting themselves against viruses, just in a needlessly expensive and uncomfortable way that could be accomplished as well with a surgical mask.
    - eveningcoffee 7y ago
      There is also change that wearer is using it properly and gets better protection that is not possible with a surgical mask.
      - yodon 7y ago
        Except the peer reviewed journal article we are discussing here shows that medical workers, who are trained in mask usage, did not receive any additional benefits from N95 masks over conventional surgical masks. N95 is important for what it's important for but where it isn't it's just security theater. Peer-reviewed meta analysis shows no added benefit of N95 masks over surgical masks for respiratory viruses, including for trained mask users.
        eveningcoffee 7y ago
        I think you are referring to this study https://www.cmaj.ca/content/188/8/567 https://www.cmaj.ca/content/188/8/567 Although N95 respirators appeared to have a protective advantage over surgical masks in laboratory settings, our meta-analysis showed that there were insufficient data to determine definitively whether N95 respirators are superior to surgical masks in protecting health care workers against transmissible acute respiratory infections in clinical settings.
        yodon 7y ago
        You are correct on the citation (it's at the top of the page so I didn't think it needed to be re-cited). My read is the researchers found that in actual daily use with trained mask users there was no benefit in respiratory virus infection prevention from N95 over traditional surgical masks (laboratory testing doesn't mean people working in a laboratory, it means a controlled experimental test setting as distinct from actual real world usage). Are you reading a different conclusion from that paper? As I read it, their meta analysis strongly suggests that as far as viral respiratory diseases go, N95 masks add nothing but cost, discomfort, and security theater when compared with cheaper, more comfortable, and easier to wear surgical masks.
rdtsc 7y ago
> N95 respirators are often considered uncomfortable for regular use, and improper wearing or adjustment of the respirator because of discomfort could lead to inadvertent face contamination, thus negating the potential protective benefit After wearing that kind of mask for short periods of time, I remember doing all of those things: not putting it on properly at first, adjusting it multiple times with the hands up against my face and so on. The is also an element of a false sense of security from wearing it. “I am wearing a mask so I don’t have to worry about getting sick and don’t have to take other precautions”. That’s probably the more dangerous part about it.
RemoteIsHeaven 7y ago
I used to do a lot of drywall work and N95 respirators are just not designed for regular extended use. If mounted properly, they will restrict the airflow and raise the temperature of your face. I would perspire heavily. Also, unless proper handling techniques are used, the chances of contaminating the insides of the mask with the virus and then continuing to breathe it will worsen the situation compared to not wearing it at all. A N95 respirator is not something to slap on willy nilly without training. I think a regular person who has never worn a N95 respirator before and does not use proper handling techniques is exposing themselves to increased risk than wearing a simpler surgical mask that's more intuitive to use.
- benjohnson 7y ago
  I find them bearable if I'm not doing physical labor.
- eveningcoffee 7y ago
  I have found only certain 3M valved models comfortable to use. It is crucial to adjust the nose clamp and it is highly beneficial to limit the facial hair. Having a valve is essential for comfortable use and for having a proper seal (there is too much air pressure when breathing out and the air will press out from the sides). In medical setting this will mean that the respirator will only efficiently protect the wearer (spread of droplets should be still limited). The face under the mask will get easily sweaty and the mask will get smelly from the inside while doing physical work. My experience is that 1 mask will at best last a day for construction work. There are other criteria when using in the medical setting. I am not expert in this field. If used in medical setting then you should keep in mind that if you take your mask off then you may contaminate yourself with the the pathogen on the outside of the mask. The same applies for trying to put the mask back on. It is therefore sensible to avoid reuse whenever possible. If you do not use protective glasses then you are first risking with direct exposure to the pathogen through the eyes. In addition you are risking the exposure by first touching the mask (to adjust it for example) and then touching your eyes. I think it does not follow that it is not sensible to use respirators but users should acknowledge that setting up a proper usage procedure is complicated and following the proper use is very difficult and will require a lot of attention and I should not be practiced casually by the untrained people.
rkagerer 7y ago
Results of our systematic review and meta-analysis show that there was no significant difference between N95 respirators and surgical masks when used by health care workers to prevent transmission of acute respiratory infections from patients. However, wide 95% CIs from our meta-analysis must be interpreted as insufficient evidence to determine whether there is a clinically significant difference. Findings from the surrogate exposure studies suggest that N95 respirators are superior to surgical masks for filter penetration, face-seal leakage and total inward leakage under laboratory conditions. It was not surprising to find that N95 respirators were generally more efficient filters with better face-seal characteristics than surgical masks when tested in the laboratory.

34 points by luu 7y ago

This is great news, particularly after seeing a huge fraction of N95 wearers in Northern California last summer wear the masks incorrectly in ways that made their presence useless.

AstralStorm 7y ago
What great news? They found mostly no difference in risk vs surgical masks...
- yodon 7y ago
  Correct. Surgical masks help. N95 masks help exactly as much as surgical masks. Poorly worn N95 masks are equivalent to surgical masks, therefore poorly worn N95 masks help as much as properly worn N95 masks. The US is going to be full of people wearing N95 masks incorrectly. This paper says that's ok they are still protecting themselves against viruses, just in a needlessly expensive and uncomfortable way that could be accomplished as well with a surgical mask.
  - eveningcoffee 7y ago
    There is also change that wearer is using it properly and gets better protection that is not possible with a surgical mask.
    - yodon 7y ago
      Except the peer reviewed journal article we are discussing here shows that medical workers, who are trained in mask usage, did not receive any additional benefits from N95 masks over conventional surgical masks. N95 is important for what it's important for but where it isn't it's just security theater. Peer-reviewed meta analysis shows no added benefit of N95 masks over surgical masks for respiratory viruses, including for trained mask users.
      - eveningcoffee 7y ago
        I think you are referring to this study https://www.cmaj.ca/content/188/8/567 https://www.cmaj.ca/content/188/8/567 Although N95 respirators appeared to have a protective advantage over surgical masks in laboratory settings, our meta-analysis showed that there were insufficient data to determine definitively whether N95 respirators are superior to surgical masks in protecting health care workers against transmissible acute respiratory infections in clinical settings.
        yodon 7y ago
        You are correct on the citation (it's at the top of the page so I didn't think it needed to be re-cited). My read is the researchers found that in actual daily use with trained mask users there was no benefit in respiratory virus infection prevention from N95 over traditional surgical masks (laboratory testing doesn't mean people working in a laboratory, it means a controlled experimental test setting as distinct from actual real world usage). Are you reading a different conclusion from that paper? As I read it, their meta analysis strongly suggests that as far as viral respiratory diseases go, N95 masks add nothing but cost, discomfort, and security theater when compared with cheaper, more comfortable, and easier to wear surgical masks.

rdtsc 7y ago

> N95 respirators are often considered uncomfortable for regular use, and improper wearing or adjustment of the respirator because of discomfort could lead to inadvertent face contamination, thus negating the potential protective benefit After wearing that kind of mask for short periods of time, I remember doing all of those things: not putting it on properly at first, adjusting it multiple times with the hands up against my face and so on. The is also an element of a false sense of security from wearing it. “I am wearing a mask so I don’t have to worry about getting sick and don’t have to take other precautions”. That’s probably the more dangerous part about it.

RemoteIsHeaven 7y ago

I used to do a lot of drywall work and N95 respirators are just not designed for regular extended use. If mounted properly, they will restrict the airflow and raise the temperature of your face. I would perspire heavily. Also, unless proper handling techniques are used, the chances of contaminating the insides of the mask with the virus and then continuing to breathe it will worsen the situation compared to not wearing it at all. A N95 respirator is not something to slap on willy nilly without training. I think a regular person who has never worn a N95 respirator before and does not use proper handling techniques is exposing themselves to increased risk than wearing a simpler surgical mask that's more intuitive to use.

benjohnson 7y ago
I find them bearable if I'm not doing physical labor.
eveningcoffee 7y ago
I have found only certain 3M valved models comfortable to use. It is crucial to adjust the nose clamp and it is highly beneficial to limit the facial hair. Having a valve is essential for comfortable use and for having a proper seal (there is too much air pressure when breathing out and the air will press out from the sides). In medical setting this will mean that the respirator will only efficiently protect the wearer (spread of droplets should be still limited). The face under the mask will get easily sweaty and the mask will get smelly from the inside while doing physical work. My experience is that 1 mask will at best last a day for construction work. There are other criteria when using in the medical setting. I am not expert in this field. If used in medical setting then you should keep in mind that if you take your mask off then you may contaminate yourself with the the pathogen on the outside of the mask. The same applies for trying to put the mask back on. It is therefore sensible to avoid reuse whenever possible. If you do not use protective glasses then you are first risking with direct exposure to the pathogen through the eyes. In addition you are risking the exposure by first touching the mask (to adjust it for example) and then touching your eyes. I think it does not follow that it is not sensible to use respirators but users should acknowledge that setting up a proper usage procedure is complicated and following the proper use is very difficult and will require a lot of attention and I should not be practiced casually by the untrained people.

rkagerer 7y ago

Results of our systematic review and meta-analysis show that there was no significant difference between N95 respirators and surgical masks when used by health care workers to prevent transmission of acute respiratory infections from patients. However, wide 95% CIs from our meta-analysis must be interpreted as insufficient evidence to determine whether there is a clinically significant difference. Findings from the surrogate exposure studies suggest that N95 respirators are superior to surgical masks for filter penetration, face-seal leakage and total inward leakage under laboratory conditions. It was not surprising to find that N95 respirators were generally more efficient filters with better face-seal characteristics than surgical masks when tested in the laboratory.