Thanks a lot for the in depth analysis, and great analysis on the efficacy of N-95 masks.
However, I think that because of the whole politicization of mask wearing most discussion has missed a crucial point (and I have been guilty of this as well): In situations where people are ready to wear masks (shops, public transport) infection risk is not high and surgical masks are enough. In situations where people generally do not wear masks (bars, restaurants, private meetings at home, all day at your workplace) risk is higher but willingness to wear masks lower. It is my understanding that this is where most of the infections happen, at least in Europe. KN95 masks have been more uncomfortable to wear than surgical ones in my experience, so my presumption is that N95 masks are not so comfortable that people will wear them all day ( please correct me if I am wrong).
This does not mean that there are some situations wear N95 masks for the general population might be beneficial like barbershops or doctor visits. It just does not seem to me that there is a lot of potential to get R to below 1 with mask wearing.
There might also be some value in designing face coverings that people would wear in more situations. For example these Japanese researchers claim to have a face shield design that prevents airborne spread much more efficiently.
I think you’re right that the magnitude of the benefit from the program depends heavily on how many people end up choosing to use the mask, especially in situations where they are more likely to contract the disease. Individuals will ultimately make a personal decision based on trade-offs between the probability of contracting the virus, comfort, convenience, and even fashion.
I also think there is significant heterogeneity in terms of how people weigh these factors. I do think that there are a significant number of people who, net of these factors, would decide that the benefits of wearing a medical-grade respirator in situations where they are more likely to contract the virus outweighs the costs. These could be seniors, people with preexisting conditions, people who don’t find the respirator uncomfortable, or people who are just risk averse.
I also think that there are currently significant numbers of people who would like to wear medical-grade respirators, but who are not currently able to get them. I have friends that are teachers that are required to teach in person that want a medical-grade respirator, but are not able to get one. As I noted above, there is still a shortage of respirators even for frontline medical workers (see https://www.washingtonpost.com/business/scarcity-of-raw-material-still-squeezes-n95-mask-makers/2020/09/10/94586834-f31e-11ea-8025-5d3489768ac8_story.html). I think there are probably enough people in this category, that you could make some dent in the infection rate with this policy, though how much depends on people’s behavior.
Also, one of the general takeaways is that, even if the benefits end up being modest (e.g. you reduce the infection rate, but not below 1 in all areas), the relative cost is so cheap that I think it’s worth it to give it a shot.
A few other points:
-As part of the program, it would be great to do randomized control trials with different types of respirators (e.g. different designs that meet the N-95 standard, enhanced N-99 or N-100 designs). There may be some sort of trade-off between comfort and protection (granted that the N-95 threshold is met), and perhaps going more on the side of comfort is optimal because the benefit from higher compliance outweighs the slightly lower protection. There may also be an N-95 design that is already produced (or gets produced for the program) that is just more comfortable and gets higher compliance, and we’d be able to figure that out. That face shield you mentioned is really cool! You could also pilot something like that as part of this program, and perhaps that wins out.
-Along these lines, I also considered adding another point, which would be creating a program called the “N-95 for all Studio,” where fashion designers or people like that could add designs to the respirators to make them look cool. You could imagine charging someone $2 or something to get the “New York Yankees N-95″ or the “Tom Ford N-95” or whatever.
-Also as winter comes in the Northern Hemisphere and as more activity moves inside and the ability to ventilate rooms goes down, there will likely be more spaces with a higher concentration of aerosols. The benefit of wearing a respirator vs. cloth mask or surgical mask goes up in this situation, so this would affect people’s behavior.
-I’d also emphasize the benefits of this policy for preparing for future pandemics. It so happens that SARS-COV-2 has a case fatality rate ~1%, and this is quite heterogeneous depending on your age and existing health. If there is a respiratory-transmitted pandemic that has a 30% case fatality rate, then the benefits of wearing a respirator will be way higher versus the costs from inconvenience, discomfort, etc.
Note that the shield claims to block droplets, but not aerosols. Aerosols will go around any shield. Even this shield with some loosefitting fabric only blocked ~10% of aerosols. Making it tight fitting with an elastic band improves it. But really what would be much safer is surgical mask material or N-95 material that is tightfitting.
I do think that appearance is critical, at least in developed countries. In my experience, most people use only cloth masks, which block about 1⁄4 of aerosols. Moving to a surgical mask blocks about three quarters, which is an enormous improvement. There are concerns about long reuse of mass that are designed to be disposable, but they are doing UV treatment, and an easy thing is just putting it in an oven at about 80C for 45 minutes. A compromise could be a surgical mask underneath an attractive cloth mask, which is still easier to breath than N-95. Surgical masks seem to be easily available, and some are even attractive.
Thanks a lot for the in depth analysis, and great analysis on the efficacy of N-95 masks.
However, I think that because of the whole politicization of mask wearing most discussion has missed a crucial point (and I have been guilty of this as well): In situations where people are ready to wear masks (shops, public transport) infection risk is not high and surgical masks are enough. In situations where people generally do not wear masks (bars, restaurants, private meetings at home, all day at your workplace) risk is higher but willingness to wear masks lower. It is my understanding that this is where most of the infections happen, at least in Europe. KN95 masks have been more uncomfortable to wear than surgical ones in my experience, so my presumption is that N95 masks are not so comfortable that people will wear them all day ( please correct me if I am wrong).
This does not mean that there are some situations wear N95 masks for the general population might be beneficial like barbershops or doctor visits. It just does not seem to me that there is a lot of potential to get R to below 1 with mask wearing.
There might also be some value in designing face coverings that people would wear in more situations. For example these Japanese researchers claim to have a face shield design that prevents airborne spread much more efficiently.
This is a really good point!
I think you’re right that the magnitude of the benefit from the program depends heavily on how many people end up choosing to use the mask, especially in situations where they are more likely to contract the disease. Individuals will ultimately make a personal decision based on trade-offs between the probability of contracting the virus, comfort, convenience, and even fashion.
I also think there is significant heterogeneity in terms of how people weigh these factors. I do think that there are a significant number of people who, net of these factors, would decide that the benefits of wearing a medical-grade respirator in situations where they are more likely to contract the virus outweighs the costs. These could be seniors, people with preexisting conditions, people who don’t find the respirator uncomfortable, or people who are just risk averse.
I also think that there are currently significant numbers of people who would like to wear medical-grade respirators, but who are not currently able to get them. I have friends that are teachers that are required to teach in person that want a medical-grade respirator, but are not able to get one. As I noted above, there is still a shortage of respirators even for frontline medical workers (see https://www.washingtonpost.com/business/scarcity-of-raw-material-still-squeezes-n95-mask-makers/2020/09/10/94586834-f31e-11ea-8025-5d3489768ac8_story.html). I think there are probably enough people in this category, that you could make some dent in the infection rate with this policy, though how much depends on people’s behavior.
Also, one of the general takeaways is that, even if the benefits end up being modest (e.g. you reduce the infection rate, but not below 1 in all areas), the relative cost is so cheap that I think it’s worth it to give it a shot.
A few other points:
-As part of the program, it would be great to do randomized control trials with different types of respirators (e.g. different designs that meet the N-95 standard, enhanced N-99 or N-100 designs). There may be some sort of trade-off between comfort and protection (granted that the N-95 threshold is met), and perhaps going more on the side of comfort is optimal because the benefit from higher compliance outweighs the slightly lower protection. There may also be an N-95 design that is already produced (or gets produced for the program) that is just more comfortable and gets higher compliance, and we’d be able to figure that out. That face shield you mentioned is really cool! You could also pilot something like that as part of this program, and perhaps that wins out.
-Along these lines, I also considered adding another point, which would be creating a program called the “N-95 for all Studio,” where fashion designers or people like that could add designs to the respirators to make them look cool. You could imagine charging someone $2 or something to get the “New York Yankees N-95″ or the “Tom Ford N-95” or whatever.
-Also as winter comes in the Northern Hemisphere and as more activity moves inside and the ability to ventilate rooms goes down, there will likely be more spaces with a higher concentration of aerosols. The benefit of wearing a respirator vs. cloth mask or surgical mask goes up in this situation, so this would affect people’s behavior.
-I’d also emphasize the benefits of this policy for preparing for future pandemics. It so happens that SARS-COV-2 has a case fatality rate ~1%, and this is quite heterogeneous depending on your age and existing health. If there is a respiratory-transmitted pandemic that has a 30% case fatality rate, then the benefits of wearing a respirator will be way higher versus the costs from inconvenience, discomfort, etc.
Note that the shield claims to block droplets, but not aerosols. Aerosols will go around any shield. Even this shield with some loosefitting fabric only blocked ~10% of aerosols. Making it tight fitting with an elastic band improves it. But really what would be much safer is surgical mask material or N-95 material that is tightfitting.
I do think that appearance is critical, at least in developed countries. In my experience, most people use only cloth masks, which block about 1⁄4 of aerosols. Moving to a surgical mask blocks about three quarters, which is an enormous improvement. There are concerns about long reuse of mass that are designed to be disposable, but they are doing UV treatment, and an easy thing is just putting it in an oven at about 80C for 45 minutes. A compromise could be a surgical mask underneath an attractive cloth mask, which is still easier to breath than N-95. Surgical masks seem to be easily available, and some are even attractive.