Microcovid.org seems to think that a “thick and snug” cloth masks cuts risk to 2/3 vs no mask, a surgical mask to 1/2, a non-fitted N95, KN95, or FFP2 to 1/3, a sealed N95 to 1/8, a P100 respirator to 1/20. (They also estimate the impact of others’ wearing masks, which interestingly does not fully match the ranking of impact for you wearing a mask.) (Their sources and methodology are here, updated Jan 2021: https://www.microcovid.org/paper/14-research-sources#masks).
I haven’t dug deep into this, but it suggests that “If we should wear anything, it should be elastomeric respirators with P100 filters or DIY PAPRs (along with eye protection), not masks” is misleadingly hyperbolic. (Of course the PPE you mention is best, but it I’d think we should be encouraging people to wear the most effective protection feasible for them.)
Microcovid.org seems to be using an outdated source, “Howard et al. Evidence Review (version 4 from Oct 2020),” but frankly, it doesn’t matter much anyway since we know that masks (mostly the cloth and surgical kind) couldn’t stop the more contagious variants that caused the winter wave nor could masks stop the UK’s massive surge of Delta infections.
If masks were the only PPE available, doing a hail mary by wearing them might be okay, but since vastly better PPE is readily available today, advising people to wear poor protection makes no sense.
Microcovid.org seems to be using an outdated source, “Howard et al. Evidence Review (version 4 from Oct 2020),
Do you have newer sources that you think render Howard et al obsolete? (That’s my most important question in reply to your comment… I responded to your other arguments for the sake of completeness, but I would personally find it most helpful if you had thoughts on the above (as may others, I’d imagine, as a lot of people are using microcovid.org.)
frankly, it doesn’t matter much anyway since we know that masks (mostly the cloth and surgical kind) couldn’t stop the more contagious variants that caused the winter wave nor could masks stop the UK’s massive surge of Delta infections
I don’t follow how the fact that masks failed to “stop the variants or surge” means they are poor protection, or not worth wearing. Unless the claim is that masks are 100% protective against COVID transmission, they can still substantially reduce risk even if they failed to stop the variants or surge.
If masks were the only PPE available, doing a hail mary by wearing them might be okay, but since vastly better PPE is readily available today, advising people to wear poor protection makes no sense.
I imagine plenty of people (myself included) find it embarrassing, uncomfortable, and inconvenient to wear a PAPR (and to a lesser extent, a P100). It may be worth encouraging people to favor those more protective PPE, but it’s worth making recommendations that people are actually likely to follow. It’s not all-or-nothing.
The best study (an RCT) I’ve seen claims that cloth masks made no statistical difference in case reduction, whereas surgical masks reduced risk by 11% and 35% for people over 60. The study authors speculate that if more people wore masks (less than 50% did), this risk reduction would probably increase. The study was done in Bangladesh from November to January, and I suspect that the variants in circulation at that time were a lot closer to the less contagious original strain. If that’s the case, it would be less likely that more mask wearing would increase risk reduction as the authors claim.
Effective PPE could have stopped the surge, whereas masks didn’t. Therefore, masks offer poor protection. Studies likes these only quantify how poor that protection actually is.
Recommendations should be based on the best approaches available rather than on trying to guess the personal preferences of most people. I’m sure that the “embarrassing, uncomfortable, and inconvenient” argument was leveled against masks at the start of the pandemic but most people don’t complain about them too much today. The same mistake was repeated during the winter surge for disposable N95s. However, there were some exceptions like Germany and California which started recommending N95-equivalent PPE. I find N95s too uncomfortable to wear, but I feel a lot better wearing elastomerics. Should my subjective personal preferences form the basis of general recommendations? No, and I don’t see why your preferences or speculations about the preferences of others should either.
Thanks for that reply. I’m realizing that part of the disagreement here is that I was vague and used “mask” to refer to n95s as well. (I’ve edited the post to be less vague in that regard). I agree that it makes sense to wear the most effective PPE someone is willing to, and it’s interesting to hear that you find elastometrics more comfortable.
Would you be willing to share which elastometrics you’ve liked? I started looking at P100s for the first time yesterday, but there is a bit less discussion of them than N95s.
While disposable N95 respirators can sometimes offer better protection for the wearer than any mask, they’re not that great due to the generally poor fit they provide.
Despite the high risk of leaks, N95s are probably a better solution for source control than masks due to their ability to filter out aerosols.
Reusable elastomerics offer better fit and more protection (N100) than N95s. There’s also somenon-anecdotal evidence that elastomerics are more comfortable than N95s. For me, elastomerics are more comfortable than even a surgical mask (due to less humidity and heat buildup) if wear time is long enough and if not engaging in a lot of physical activity.
The best N100/P100 particulate filter for a respirator is probably the 3M 2291 due to its lower pressure drop (that means it takes less effort to inhale) and that restricts respirator choices to the 3M 5000, 6000, 6500, and 7500 series (excluding respirators with full facepieces). Anecdotally, the effort to breath through the 2291 seems almost the same as breathing through an N95 filter. The 6500 and 7500 series probably has a somewhat better faceseal due to the more pliable silicone material that they use. Silicone also makes the faceseal hypoallergenic. I’ve seen some anecdotal reports that the 7500 is more comfortable than the 6500 due to (supposedly) slightly more pliable silicone. Personally, I’ve felt no significant difference in comfort between the rubber faceseal of the 6000 and the silicone faceseal of the 7500.
It’s been claimed that a lot of fake filters are on the market, so I’d try to acquire them from a reputable source like an established hardware distributor.
Microcovid.org seems to think that a “thick and snug” cloth masks cuts risk to 2/3 vs no mask, a surgical mask to 1/2, a non-fitted N95, KN95, or FFP2 to 1/3, a sealed N95 to 1/8, a P100 respirator to 1/20. (They also estimate the impact of others’ wearing masks, which interestingly does not fully match the ranking of impact for you wearing a mask.) (Their sources and methodology are here, updated Jan 2021: https://www.microcovid.org/paper/14-research-sources#masks).
I haven’t dug deep into this, but it suggests that “If we should wear anything, it should be elastomeric respirators with P100 filters or DIY PAPRs (along with eye protection), not masks” is misleadingly hyperbolic. (Of course the PPE you mention is best, but it I’d think we should be encouraging people to wear the most effective protection feasible for them.)
Microcovid.org seems to be using an outdated source, “Howard et al. Evidence Review (version 4 from Oct 2020),” but frankly, it doesn’t matter much anyway since we know that masks (mostly the cloth and surgical kind) couldn’t stop the more contagious variants that caused the winter wave nor could masks stop the UK’s massive surge of Delta infections.
If masks were the only PPE available, doing a hail mary by wearing them might be okay, but since vastly better PPE is readily available today, advising people to wear poor protection makes no sense.
Took a while to reply to this, sorry.
Do you have newer sources that you think render Howard et al obsolete? (That’s my most important question in reply to your comment… I responded to your other arguments for the sake of completeness, but I would personally find it most helpful if you had thoughts on the above (as may others, I’d imagine, as a lot of people are using microcovid.org.)
I don’t follow how the fact that masks failed to “stop the variants or surge” means they are poor protection, or not worth wearing. Unless the claim is that masks are 100% protective against COVID transmission, they can still substantially reduce risk even if they failed to stop the variants or surge.
I imagine plenty of people (myself included) find it embarrassing, uncomfortable, and inconvenient to wear a PAPR (and to a lesser extent, a P100). It may be worth encouraging people to favor those more protective PPE, but it’s worth making recommendations that people are actually likely to follow. It’s not all-or-nothing.
The best study (an RCT) I’ve seen claims that cloth masks made no statistical difference in case reduction, whereas surgical masks reduced risk by 11% and 35% for people over 60. The study authors speculate that if more people wore masks (less than 50% did), this risk reduction would probably increase. The study was done in Bangladesh from November to January, and I suspect that the variants in circulation at that time were a lot closer to the less contagious original strain. If that’s the case, it would be less likely that more mask wearing would increase risk reduction as the authors claim.
Effective PPE could have stopped the surge, whereas masks didn’t. Therefore, masks offer poor protection. Studies likes these only quantify how poor that protection actually is.
Recommendations should be based on the best approaches available rather than on trying to guess the personal preferences of most people. I’m sure that the “embarrassing, uncomfortable, and inconvenient” argument was leveled against masks at the start of the pandemic but most people don’t complain about them too much today. The same mistake was repeated during the winter surge for disposable N95s. However, there were some exceptions like Germany and California which started recommending N95-equivalent PPE. I find N95s too uncomfortable to wear, but I feel a lot better wearing elastomerics. Should my subjective personal preferences form the basis of general recommendations? No, and I don’t see why your preferences or speculations about the preferences of others should either.
Thanks for that reply. I’m realizing that part of the disagreement here is that I was vague and used “mask” to refer to n95s as well. (I’ve edited the post to be less vague in that regard). I agree that it makes sense to wear the most effective PPE someone is willing to, and it’s interesting to hear that you find elastometrics more comfortable.
Would you be willing to share which elastometrics you’ve liked? I started looking at P100s for the first time yesterday, but there is a bit less discussion of them than N95s.
While disposable N95 respirators can sometimes offer better protection for the wearer than any mask, they’re not that great due to the generally poor fit they provide.
Despite the high risk of leaks, N95s are probably a better solution for source control than masks due to their ability to filter out aerosols.
Reusable elastomerics offer better fit and more protection (N100) than N95s. There’s also some non-anecdotal evidence that elastomerics are more comfortable than N95s. For me, elastomerics are more comfortable than even a surgical mask (due to less humidity and heat buildup) if wear time is long enough and if not engaging in a lot of physical activity.
The best N100/P100 particulate filter for a respirator is probably the 3M 2291 due to its lower pressure drop (that means it takes less effort to inhale) and that restricts respirator choices to the 3M 5000, 6000, 6500, and 7500 series (excluding respirators with full facepieces). Anecdotally, the effort to breath through the 2291 seems almost the same as breathing through an N95 filter. The 6500 and 7500 series probably has a somewhat better faceseal due to the more pliable silicone material that they use. Silicone also makes the faceseal hypoallergenic. I’ve seen some anecdotal reports that the 7500 is more comfortable than the 6500 due to (supposedly) slightly more pliable silicone. Personally, I’ve felt no significant difference in comfort between the rubber faceseal of the 6000 and the silicone faceseal of the 7500.
It’s been claimed that a lot of fake filters are on the market, so I’d try to acquire them from a reputable source like an established hardware distributor.
This is incredibly helpful, thank you!