You’re listening to a press conference from the Harvard T.H. School of Public Health with Joseph Allen, associate professor of exposure assessment science and director of the Healthy Buildings Program. This call was recorded at 10 a.m. Eastern Time on Monday, February 1st.
MODERATOR: Dr. Allen, do you have any opening remarks?
JOSEPH ALLEN: Yeah, thanks so much, Nicole, and thanks for all who have joined us. Just a quick remark on the background, so my background is exposure risk science. And I’ve been doing forensic investigations of sick buildings for over a decade. And it’s a lot of that training and practice that is the basis for a lot of the recommendations I’m giving on how to protect we in any indoor environment, be in an airplane, home, school office, laboratory, whatever it is. We’ve been doing this for a long time. We know how to keep people safe in buildings. It all comes down to aligning controls against the hazard. And in this case, a shifting hazard, a biological hazard. And I’ve been advising organizations, everything from special advisor to reopening jury trials in Massachusetts, courthouses, homeless shelters, childcare facilities, also schools, universities, biotech, pharma, entertainment. So really, I’ve seen across a wide swath of the US economy on the different organizations and how they’re approaching control measures and risk in school. And lastly, I’ll say just on the credentialing side, I guess is and related is that the work is international, too. I’m a commissioner on The Lancet COVID-19 Commission, and I chair their task force on safe work, safe schools and safe travel. So, I’m happy to answer questions on any of the topics that Nicole mentioned or even beyond that, whatever is interesting to you. So thanks for joining us.
MODERATOR: All right, first question.
Q: Thank you, Dr. Allen. I have a couple of questions, but some of them are probably pretty basic, maybe to other people. But I had read somewhere that there’s a growing call to provide in N95 masks to essential workers, that that can make a big difference. To teachers and essential workers as well, I guess always, how to balance that against the need for health care workers. But what are your thoughts on that?
JOSEPH ALLEN: All right, great question. And I wrote a piece on this in The Washington Post last week specifically on this topic, and I can take a minute or two to explain it. Really, we’re past the point where any mask will do. That was that was great last winter and actually into the early spring where there was, let’s say, widespread reluctance or wasn’t really the cultural norm in the US to wear masks. And we had a shortage of high quality N95 masks for health care. So the first piece I wrote in The Washington Post was actually in early April saying that the public health debate is over, everyone needs to be wearing a mask. And at that point it was anything is better than nothing. Cloth masks, great. But we’ve learned a lot since that time. And in terms of what constitutes a good mask, and there are two factors that are critically important. You have to think about the two f’s, filtration and fit. In terms of filtration, I think it’s intuitive or hopefully most people know, the N95 means ninety five percent effective capture efficiency for respiratory aerosols that may carry the virus. But it’s really the Wild West out there for everybody else trying to figure out if their cloth mask is good or if they see a mask on Amazon they want to buy, whether that’s a good mask. A cloth mask can be anywhere from 20 percent effective, up to 70 percent effective depending on its construction, the type of fabric used. Blue surgical mask can get you roughly 70 percent capture efficiency and the N95 and other masks can do much better. That’s on the filtration side.
Second side is on fit, the second f. And this makes sense. You know, if you see a blue surgical mask that’s great, good filtration. But a lot of times you’ll see a gap on the side or on the top. So the fit is poor. So fit also matter should be the bridge of your nose, flush around your cheeks and wrapping under your chin. When you do all of this, you can get good filtration efficiencies. Now you should also select the mask based on the level of risk or the activity in the level of risk associated with that activity. And here’s something that’s missed often in the benefits of universal masking is that the respiratory aerosols have to go through two masks. That means two filters. So even if everyone’s wearing a good surgical mask and getting 70 percent efficiency, capture efficiency of these particles, that’s not N95, but the fact that particles have to go through your mask and my mask means that the combined effect of two 70 percent mass is greater than 90 percent if you add in distancing between the masks. And good ventilation and filtration, you further improve that and can get over ninety nine percent reduction in exposure, even from a good three-layer surgical mask. Why I made the call now for better masks is because we have widespread cases and new, more highly transmissible variants on the near horizon. Upgrading our masks to higher efficiency masks is the quickest way to reduce exposure. So I mentioned if you have two 70 percent masks to combine efficiency is over 90 percent. If you have two ninety five percent efficient masks, people wearing this in the same room, the exposure reductions greater than ninety nine percent before you even add in any other controls. So one of the problems now, as you mentioned, is that N95’s quite unbelievably are still in short supply for health care. This is a gross failing on our part as a country. We’re a year into this, we still don’t have adequate supply of basic PPE for health care workers. So in the interim, you know, the point of the piece was to say we need to do better and we need to have more of these masks produced at scale and delivered cheaply to the general public and essential workers who aren’t getting the same kind of protections as health care workers. Now, because they’re still scarce, the N95s, I’ve been giving my cheat sheet on mask selection this way, if you can find an N95, great. Next, I would go with a KF94, these are masks certified out of Korea and as the name implies, ninety four percent effective. So really good masks. They tend to have a good fit and it’s a trusted certification out of Korea. These are widely used in South Korea. Some people go to KN95s. This is a designation that’s very similar to an N95, but it’s not a US manufactured designation. I’m more cautious with these because we’ve had counterfeit N95s on the market, some producing or providing only twenty five percent capture efficiency, despite being designated 95 percent. So KN95s can be good, it just requires consumers to do a bit more homework to look up on the FDA and CDC Web sites for the links that describe the testing done on masks by different manufacturers. So said better, if you’re going to buy a KN95, you need to do your homework to be sure that it’s a mask that has been vetted and verified by the US, FDA and CDC. So in the interim, the next I would go on this list is double masking, this is a stopgap solution if someone wants good protection from readily available and cheap masks. And the idea of double masking is you wear a blue surgical mask, on top of that, you add a cloth mask, the blue surgical mask gives you a good filtration. Cloth mask will add some additional filtration, but importantly, the cloth mask improves the fit of the surgical mask. So the double masking there addresses, both filtration and fit, and is a good stopgap measure. If you’re going for a walk with a friend, you’re out in a park with a friend, a simple cloth mask is just fine. So the long answer to your question, but I want to cover some of the key topics in our op-ed from last week.
Q: And maybe that’s where I saw it. And just one quick follow up. I know most people, however, are probably getting their masks at the grocery store, a cloth mask, and they’re keeping it in their car or in the purse or someplace that’s not particularly sanitary. Does that matter in terms of its effectiveness, even if it’s sort of a bunched-up thing you pull out of your purse or if it’s washed every day or something, you know, that sort of thing? How does that impact the effectiveness?
JOSEPH ALLEN: If you have a cloth mask, you want to be washing the mask daily, you can also hang it up after you’re done using it. The virus decays or inactivates over time. So you just want to leave it out. I mean, the reason we have to do that and be careful about our masks, including how we touch them and using hand sanitizer or washing your hands after we touch our mask is because think of the reason, we’re wearing a mask. We’re essentially acknowledging that the mask is capturing infectious particles. That’s ultimately why we’re wearing a mask. So we have to treat it as such. And that makes sense. And that means if you touch your mask, if you want it indoors around other people, then you should wash your hands after you do that and you should hang it up. Either you can let it hang up in between uses or over time, or you have a cloth mask, you would wash it with these other masks we’re talking about. These are intended to be single use, but just like health care workers are extending the life of that N95 and using them for an entire shift, I would recommend the same for people purchasing that N95 or KN94, it’s a mask you can wear for the day.
Q: OK, and I had a couple of quick follow ups on that. You said that you can let a mask hang out until the virus dies. How long does it take for the virus to die if it’s just hanging out?
JOSEPH ALLEN: It’s generally pretty quick. I mean, the idea is, you know, the virus inactivates, it’s not a specific time. It’s going to depend on how much of the virus was on the mask, temperature and humidity where it’s stored. But generally, you know, over a day it’s going to be OK. The way I would do is if you have a cloth mask, I would wash it or use it for one day and then wash it. If you have one of these disposable masks, you can wear it for the day and then dispose it and use a new one, and if you’re going to reuse a cloth mask in between washing, then you should practice really good hand hygiene. So, you know, wash your hands before you put it on, wash your hands before you take it off, after you take it off.
Q: OK, thanks. And also, you have been talking about the KN95s and that there are some issues with air quality. Are there any concerns with N95s and KN94 masks and counterfeits, anything like that, or they are pretty solid quality?
JOSEPH ALLEN: So N95s you can trust. These are US certified masks. Well, I don’t know of any reports of counterfeit N95s. That’s not to say it can’t happen, I just don’t know. The KN95s, the counterfeit masks have been widely reported. And in fact, I wrote about it in this piece last week, but I also wrote about it in an article in Stat News in April with a colleague of mine from Harvard School of Public Health, David Christiani, pulmonary physician at Mass General Hospital, where we link to the warning from OSHA about KN95 masks. And even at that time, in early April, OSHA was recommending this prioritization of masks for health care workers. N95, KN95 not from China unless it’s from a manufacturer with a NIOSH certificate. Third, KN95 from China. Fourth, blue surgical mask. So we’ve known about this issue. So KN95 has been a known issue and KF94s from South Korea, I haven’t seen any reports of a counterfeit. Again, I don’t know if that’s happening. I guess it’s possible with anything, but I never would have a lot of confidence in the N95s and KF94s. And some KN95s are just fine, I just think it’s really challenging for a consumer to figure this out. It takes a bit more work. And ultimately, this is what the op-ed is about, is a call for a lot more standard increase in supply of these better masks and standardization around this. We’re a year into this pandemic. It shouldn’t take hours and hours for a consumer to try and figure out what’s a decent mask that they can use as they have to go to their job or for their kids. You know, with all the scientific innovation we’ve seen over the past year about vaccines and therapeutics and testing, it’s shocking that we haven’t seen any innovation on the side of this simple and most effective tool and that being a mask and innovation in terms of filtration and fit and comfort and even style. So people would want to wear these things out and about. We’ve really just ignored this simple tool because we haven’t produced them at scale. Even the price for N95 is ten over what it used to be to be under a dollar. Now you see these sold for five or seven or eight dollars a mask.
Q: Thank you.
MODERATOR: Next question.
Q: Good morning, thank you for taking my question. I wanted to ask you about variants and your thoughts about schools, what they need to keep in mind in terms of reopening their buildings, given the information we have presently on variants. Thank you.
JOSEPH ALLEN: Yeah, thanks for the question. So certainly, the variants, I think now widely reported and known, are more highly transmissible and at least B.1.1.7. is poised to be the dominant strain of the US in the coming weeks. And this means that schools must put in strict risk reduction measures. Now, these measures have been known for many months. My team released a report on risk reduction strategies for schools in June, and we’ve been advising schools to take these precautions, the basics around strict masking protocols, improving ventilation and filtration. I can talk about that recommendation in depth if you’d like. But here’s what I think is why it’s even more important now. I think for the schools that didn’t put in these strict controls and didn’t have cases or an outbreak or any problem through the fall, it’s possible they just got lucky. And I think the margin for getting lucky is about to shrink because of these new variants. So that means every school must put in these strict protections. I’ve been saying since June, it cannot be schools as usual. You have to start addressing these basic, so most effective and most important measure is universal masking. This must be a requirement at schools across the country. You see what happened in the U.K. and they’re really lax, among other things, they’re really lax in terms of their masking requirements. I wrote an op-ed in The Guardian maybe two weeks ago with a colleague at the School of Public Health, Bill Hanage, and another infectious disease epidemiologist at Boston University School of Public Health, Helen Jenkins, talking about masking behavior in the U.K. Shockingly, in schools, they only required mass for secondary schools, not primary schools, and only in common spaces like hallways, not in the classroom. So that doesn’t make any sense to me, and it’s something that should be corrected.
And in the U.S. context as well, we absolutely have to have masking in all of schools. Second, schools have to address the ventilation filtration question we recommend and have been recommending they target four to six air changes per hour through any combination of better filtration or better ventilation. And the logic is this. When we have these respiratory aerosols that people emit when they’re just talking or breathing and more when you talk loudly, more when you sing. These respiratory aerosols will travel beyond six feet and stay aloft for, could be hours unless they’re diluted out of the air through ventilation or filtered out of the air through filtration. So schools need to put in these controls and contrary to reports, this doesn’t have to be expensive and it doesn’t take long to do. It can be as simple as opening the window a little bit to improve ventilation, even in cold weather. My windows open right now in my office right now, it’s open three or four inches. And I can show you I’m tracking my carbon dioxide concentration in my office under eight hundred parts per million. I know that’s an acceptable level of ventilation. So this is really quite important for schools to do, not necessarily to track, but we put out the tools, and I can point to the links and resources on our Harvard Healthy Buildings team website on schools for how a school can figure out if their ventilation is acceptable. But the point I was making is that these controls don’t have to be expensive, don’t have to take a lot of time or money. And there are other stopgap measures that can help schools improve ventilation filtration without having to go through multimillion dollar, many months long improvements to aging infrastructure.
Q: Follow up question, can you talk a little bit more, you said you could go into some of the specifics of ventilation filtration. Do you mind doing that for a moment?
JOSEPH ALLEN: Sure. So I kind of touched on it a little bit in that the reason why we have to do it. So you wear masks to control source of emission and then you improve ventilation and filtration to take care of the space between masks between people. And so this target we want is four to six air changes per hour. And for reference, a typical school, if it’s meeting, the design standard gets about three air changes per hour. A home typically gets half an air change per hour, just for reference. Problem is, is that the standard that determines the acceptable ventilation rate in schools is a minimum standard not designed for infectious disease transmission. So that’s one problem. So even hitting the standard ventilation rate only gives you three changes per hour is not set for infectious disease. The bigger problem is that because we’ve so neglected our school infrastructure for decades, most schools get half of that typical school. An average of school gets one and a half changes per hour. Some schools get down to one air change per hour. So definitely not enough. You can achieve these four to six air changes through a couple of different means if you’re a building that is naturally ventilated. My room right here, you open up the window, even a couple inches, and right now the temperature gradient, even in more cold places will help drive a lot of the air exchange. That’s a good thing. If you have a mechanical system, you want to bring in more outdoor air and improve the level of filtration on the recirculated air. Most buildings, almost all buildings, recirculate a fraction of the air. That air is usually going through a filter called a MERV 8 filter, very low efficiency for capturing particles. You want to upgrade to what’s called a MERV 13 filter, to capture about 80 percent of the particle sizes we’re interested in for this virus. Third is, and I can put a graphic out there, if you’re interested, that summarizes all of this, but the third, one is higher outdoor air, either through mechanical or natural means, opening windows. Two, better filters on the recirculated air. Three, you can use a portable air cleaner with a HEPA filter. These are relatively inexpensive plug and play technology that can easily get you two, three, four or more air changes per hour in a classroom. I wrote an op-ed in August, arguing that every classroom in the US should have these and the total cost me about a billion dollars. But it’s the quickest way, it’s not a permanent fix, but it’s the quickest way to address issues around ventilation or filtration in some of our older schools and smaller rooms and classrooms.
Q: I’m sorry, I don’t want to take too much more time because there are other people on this call, so can you just address that last you mentioned the quickest way, the third. Can you just touch on that one more time for me, please? I just want to make sure I have it.
JOSEPH ALLEN: Sure. So these are portable air cleaners with HEPA filters that you can buy off the shelf at local hardware stores, big box hardware stores. You can get them online. And if you size them correctly for the room, the classroom, you can get two, three or four or more air changes per hour. We have a tool on our schools for health website schoolsforhealth.org is where my Harvard Healthy Buildings program lives. And we have a page dedicated to schools, that has a link to the portable air cleaner tool. And essentially you enter in the size of your classroom. You know, length times width, ceiling height, and then the specs from the portable air cleaner you’re thinking about something called a clean air delivery rate that I can explain. And then it tells you how many air changes per hour you’re getting. So we’ve simplified the calculation for anybody who wants to do this. And we put in a tool that shows you how to evaluate a whole bunch of different air cleaners really quickly. Now, what you’re looking for in an air cleaner is something called the clean air delivery rate, or CADR. It’s something that air cleaners, portable air cleaners report. It’s a function of how good the filter is and how much air goes across the filter. You can imagine blowing a lot of air across a poor filter. You get low clean air; you can have a great filter with a poor fan and still also not be doing much. So you want to look for a portable air cleaner with a high clean air delivery rate that has to have a HEPA filter. You don’t want any other bells and whistles. You don’t want UV or ionization. You just want to HEPA filter with a high clean air delivery rate. Rule of thumb, if you have a clean air delivery rate of three hundred for every five hundred square feet of room, you’ll get over four air changes per hour, assuming it’s eight-foot ceilings. So that’s a quick rule of thumb. And there are more details. We have a white paper that explains the science on our website and then this a link to this tool. And I’ll tip you off that we have another new tool that we’re going to publish on our website probably tomorrow. Once we get it live, it’ll be another tool for classrooms to be able to use CO2 as an indicator of how well your space is ventilated.
MODERATOR: And just give everybody a heads up. I’ve been trying to put as many links as possible into the chat, so there’s all sorts of stuff out there. Check out the Zoom chat. And I was trying to put the portable air cleaner purification report. The link for that isn’t quite transferring over well. So I’m not sure what’s going on, but it is out there on this site right here.
JOSEPH ALLEN: Thank you, Nicole.
MODERATOR: Sure. So all of this information is located in the schoolsforhealth.org website. And if you have any problems finding that after the call, let me know and I can help you.
JOSEPH ALLEN: And related, there’s another one that’s important on that list since we’re talking about ventilation, filtration. So we went out to many schools in August and actually started measuring ventilation rates with two goals in mind. One was to help the schools we’re working with. Two, is we wanted to create a guide for other schools? And we published this guide in August, a five-step guide for how to assess ventilation in schools. It’s technical, but we walk through it, we try to simplify it, and we walk through it step by step. And at the end of that report, we have examples for schools that are mechanically ventilated, schools that only have windows that can open, schools that want to use a combination of windows and portable air cleaners. And we walk through how you would assess that to determine if you’re getting enough in your classroom and even walk through if someone wants to use a CO2 monitor to assess ventilation rates. So the guidance is out there. Many schools have actually use that. I know of several big districts that have relied on both our risk reduction report as a road map for their strategy and then use the ventilation guide as their tool to guide their approach to how they assess ventilation in all their schools. And I think one entire state that I know of used our report as the guide for how to get schools reopened.
Q: Thank you.
MODERATOR: Next question.
Q: Thank you, and this is just a follow up to that great summary of schools. One of our big tech headquarters here in Silicon Valley are talking about bringing people back in June, July, August, Google saying September, I think. You summarized ventilation really well. What other measures might you suggest for these companies?
JOSEPH ALLEN: So a couple of different things, I mean, in that time frame, a lot is going to change fast. By then, we’ll be in the hundreds of millions of people vaccinated that will change the course of the spread and the disease dynamics. We’ve already seen what happens when you start to hit these kinds of numbers and places like Israel where they have high penetration in terms of vaccine uptake. So the disease dynamics will be significantly different. And importantly, hopefully, most people who are very high risk will have gotten the vaccine or certainly they’ll have had the opportunity to have gotten the vaccine. So that’s going to change things very quickly. Second, is that the landscape will be very different, I suspect, in terms of the availability and scale up of rapid antigen-based testing. And my colleague Michael Mina has been talking about this at length for a long time. But to me, it’s one of the most shocking things of 2020, how we did not as a country produce these rapid at home antigen tests and produce them at scale.
It’s shocking. It’s shocking it’s not done at this point, but I’m hopeful that the Biden Harris administration is working on this. So I think those will dramatically change the landscape. That doesn’t mean these companies don’t have to keep their controls in place. And so the controls we’re talking about is the is the basic playbook. And it’s the playbook that we know has worked from high-risk locations like health care. If you think about what health care is doing, where they’ve driven down risk, it’s just a handful of measures. They are not testing prior to the past two months. They didn’t have immunization. They weren’t testing everybody or doing daily screenings with testing, but what they were doing was strict masking with good masks, good hand hygiene and hospitals take care of their buildings, good ventilation, filtration, and they can’t do physical distancing. So even without the physical distancing, they’re able to really drive down spread with these handful of measures. I mean, it really has become crystal clear what needs to be done. And I will say this in terms of the building in particular, which is an area I’m interested in and wrote a book called Healthy Buildings that came out in April with a professor at Harvard Business School, talking about all of the ways that buildings influence our health even beyond infectious disease transmission. So while some of these controls will start to be pared back towards the end of 2021, there are things that should stay. Plexiglas should go away, but better ventilation should stay because the decades of science show that higher ventilation rates and better filtration those for infectious disease transmission, which is good for COVID, but also other infectious diseases like influenza. But also, healthy buildings are not just about disease avoidance strategies or better health is not just about disease avoidance, it’s also about health promotion. Higher ventilation rates and better filtration are associated with fewer sick building symptoms, reductions in headaches, fewer asthma attacks, better performance on cognitive function scores, thinking about kids in schools, better test scores on reading comprehension, better math scores. So there are some of these strategies that that we should have been doing anyway. And that I hope, stay, even after the immediate threat of the of COVID-19 is hopefully controlled in the time frame you’re talking about.
Q: Thank you. I’ve got a quick follow up question just to pivot back to masks briefly, I’ll put it in the chat.
MODERATOR: In the meantime, another question.
Q: Thank you. Just along the lines of that ventilation question, I haven’t read much about this. I know anecdotally one person who believes that she was infected because she lived in a condo building where many other people were infected. But she took great precautions so that was the only thing she could point to. I guess what I’m wondering is how many infections in the U.S. do you think are because of ventilation buildings and apartment buildings where maybe there’s some sort of shared ventilation system?
JOSEPH ALLEN: I think very few. So it can happen, but most of the examples we’ve seen of it happening are really have been really specific and similar to what we saw with SARS one where you might have a multi-unit apartment building with empty drain traps, let’s say, in the bathroom or in the showers. And so this can act as a conduit for air and virus passing between apartments. And we’ve seen high profile outbreaks from SARS-1and even SARS-2 through those conditions, but really rarely reported. Now, it is possible depending on how the building is designed or operated, that the air between apartments is shared in some buildings. You know, in our book we talk about one study showing that up to 30 percent of air in an apartment is shared air from an adjacent apartment. But that doesn’t necessarily mean it’s a risk as it relates to a virus, right? A lot is happening between apartments, larger volumes of air impact out on many different surfaces. So the fact that the air between apartments can communicate doesn’t necessarily mean it’s higher risk. We also don’t have evidence of transmission through duct work, and that’s probably related to a couple of different things. One is just the pure total volume of air you think it gets, the virus starts to get diluted relative to the amount of air and there are filters, even poor filters were captured, some percent of these particles. So while there is some evidence that it has happened, they’ve been very specific to failures and how the building was operator managed, and I’d say it’s unlikely. And if somebody did catch it from somebody in the building, I’d say it’s more likely they caught it by spending time in other shared locations in the building, it could be laundry, could be in the hallway, it could be in the lobby.
Q: Thank you, that’s helpful. It’s good to know, actually put that to rest. Thank you.
JOSEPH ALLEN: And it really, really depends on the building. I mean, some buildings are managed and operated terrifically in such a way that the air is totally isolated from apartment to apartment. But there are some buildings where that doesn’t happen as well. So it’s hard to generalize, but I would put it as a lower risk. Second, I would say if someone’s really concerned and this is a good strategy, if you think someone sick in your house as well, the portable air cleaner strategies, great for homes. You know, this is something I’ve never done this in the past, but I have these operating in my house. And if you size them right for your room, if you have one or two of these, again, you can get three, four, five air changes per hour of clean air through one of these devices in a room in your house. So if someone was concerned and they wanted to because of the way their building is run or they’re just concerned, this is a relatively inexpensive but it’s a you know, for a couple hundred dollars, you can get devices that provide a lot of clean air through HEPA filters.
Q: That’s great. Thanks so much.
JOSEPH ALLEN: Sure.
MODERATOR: Going back, she would like to know why N95s are still in short supply.
JOSEPH ALLEN: Well, you know, my area of expertise is not supply chain management, but I’ll tell you, I don’t think it’ll be a surprise is that almost every aspect of the pandemic was grossly mismanaged by the prior administration, who did not take it seriously. It was treated as a hoax, as you saw many quotes about this, and efforts were not made to scale up on PPE or any of the other things we needed, including testing, rapid testing. And they provided funding for rapid vaccine development and then dropped the ball on maybe the most important part or equally important part, which is the last mile of getting these distributed into people’s arms. So my hope is that the new administration is working to correct that. It’s really shocking as a country to think that we couldn’t provide a 50-cent mask to all of our health care workers. And at this point, essential workers should be getting these masks, you know, I opened my op-ed talking about the increased mortality across other workers. We talk about health care as being higher risk, but they’ve really controlled there in a high-risk environment. But they have protocols and protections in place, even if that means wearing an N95 for extended periods. But a list some of the occupations with staggering higher rates of mortality, like bakers. 50 percent higher mortality risk this year, construction workers very similar. So we have many essential workers who are working in food, carrying food through our entire food supply system and truck drivers and construction workers and grocery clerks, maids that are at much higher risk of death than previous years. And we have totally failed to provide them with the basics and in terms of adequate respiratory protection.
MODERATOR: And next question, what would standardization and innovation, better filtration or comfort better fit, what would that look like from a consumer’s perspective?
JOSEPH ALLEN: So right now, we have masks that have sufficient filtration. Ninety five percent or ninety four percent filtration efficiency is excellent. That’s what we need. We can have masks that fit better so that we don’t have where the fit is tighter around the nose, particularly in the bridge around the cheek. So there could be efforts to improve this. There have been some efforts by some individuals and small companies to develop add-ons that you would wear on top of a mask to help improve fit. Kind of like the double masking thing. I said you wear a surgical mask and then you put something on top of it to make sure that’s flush against your face. Probably most important from a consumer perspective, though, is just some standardization in terms of the guidance for what they should be wearing during which activities, and how they can have confidence that the masks their purchasing meets some minimum requirements. That’s easy for N95, but the cloth mass or three-layer masks, you can have a three-layer mask that is actually quite effective if the materials are the right materials and or you slip in a filtering layer in the middle of the mask. That’s a great solution. And people kind of like the cloth masks now. Maybe not like them, but you can customize them and get them to you know, they look nice. You can buy them different shapes and sizes that fit you best. Kids like them. There are all sorts of characters on their masks now. And so some guidance there would go a long way so people can have confidence if I’m only have low risk activities and I want to buy a good cloth mask. Well, the fact that they range from poorly performing to very high performing, how do I know it’s impossible to know. And so you have to actually do a lot of work to figure out, OK, what type of fabrics, what combination of fabrics are most important? What should I use as a filtering material in the middle? And I think some simplification and standardization there, both in terms of the communication on masks and requirements for people producing and selling these to label their masks, meeting some minimum performance standard. We’re a full year into this, I get questions all the time on is this a good mask? A friend, colleague, will send me a link. What do you think about this? And that shouldn’t be happening at this point. That should have been fixed.
MODERATOR: One more question she would like to know, is it still necessary to wipe down mail packages, et cetera, are there any known cases of transmission this way?
JOSEPH ALLEN: So two things to research that point you to. The answer is no, it’s not necessary. And we wrote a piece, Marc Lipsitch and I. Marc Lipsitch directs our Harvard School of Public Health Center for Communicable Disease Dynamics. We wrote a piece in I think it was late March. I think we wrote it together; we wrote a couple together, maybe he and I didn’t write that one, I forget. It is in The Washington Post, basically putting into context the risk or low risk from accepting packages or going grocery shopping and wrote it at the time in response to a YouTube video, is getting 20 million hits showing a doctor wiping down every ketchup bottle they bought at the grocery store. That didn’t make a lot of sense for a lot of reasons, but mostly because the risks from contaminated surfaces was very low and is better controlled through good hand hygiene. Put away your groceries, wash your hands. Really simple. Same thing with your mail. You pick your mail up, you wash your hands. It’s fine. If you’re really concerned, you could leave it sit for a couple hours. And in that article, I walk through why it’s what we knew at the time.
And I’ll tell you something we wrote more recently, but at the time even we knew that the risk from contaminated surfaces is very low. And the causal chain or the sequence of events that would have to happen for a piece of mail to be a source of transmission would be the mail carrier or package person delivering the package would have to cough or sneeze onto the package and really put a high viral load on the package almost immediately before delivering to you. You would have to take that package right away and touch that same spot, thereby transferring some of the virus from package onto your hands, although that would be like a log reduction or order of magnitude reduction. Then you’d have to touch immediately to one of your mucous membranes, another log reduction. And so is it possible that that could happen? Yes. Is it likely? No. In fact, we call the risk to minimize risk. It’s a low and manageable risk through handwashing. More recently, I wrote an op-ed with two other colleagues around the country, Professor Charles Haas and Professor Linsey Marr. This is an op-ed in The Washington Post, I think it was November, highlighting that we’re over cleaning surfaces now that wasn’t necessarily about packages or grocery stores, but it’s related. And the opening sentence is something to the effect of we don’t have a single documented case of fomite transmission. I think that surprises a lot of people. Fomite, just quickly, is any inanimate surface that can be a source of transference for the virus. So a doorknob could be a fomite, a package could be a fomite, phone at a desk could be a fomite, such as the name for any service that can transfer the virus. So can it happen? Yes, it can happen. But we have little evidence that it is happening. And even if it is happening, this is not what’s driving the pandemic by any means. In other words, if you think about the high-profile outbreaks, take the choir practice. 50 plus people, one person infected, 50 plus infected out of sixty-one or sixty-two. Hard to explain that through fomite transmission. In fact, any of the high-profile breaks is hard to explain through fomite transmission, through air and aerosols. Yeah, that makes a lot of sense, these high attack rates. So, you know, I wrote an op-ed in May on the link between airborne transmission and super spreading events that this was the key for how one person can affect many and the super speed advances, understanding the dynamics of airborne transmission. So as transmission beyond six feet indoors, in places with lower no ventilation or filtration, and so my transmission has gotten too much attention, in my opinion, and many organizations we’ve seen have been over cleaning and spending a lot of money, hundreds, sometimes hundreds of thousands of dollars on cleaning surfaces every hour. Despite this being a very low risk and more importantly, despite there being better control measures, just have people wash their hands or put out hand sanitizer is much more effective. And so that’s why we wrote that piece. Now, I would take one step, big picture. You know, it took almost 10 months for CDC and World Health Organization to acknowledge that airborne transmission was happening starting last winter through the spring and even the summer. They were saying that most of the transmission was close contact, which is important, certainly, and with some contribution from fomites or contaminated surfaces. But this was really a mistake and it led to a lot of people spending time, valuable resources, both time and money on cleaning surfaces, despite it not being really a high risk. And many times, this was at the expense of focusing on interventions that really provide a benefit like building level ventilations. And so we focused on shared services, but not shared air. And that was a big mistake.
Q: Thank you very much.
MODERATOR: Next question.
Q: Hello again. I just wanted to ask you about your opinion piece in The Washington Post at the end of December regarding schools. Touching on the variants and why you think schools should remain open, given that a month has passed since that piece, what are your thoughts presently concerning variants and whether schools should be open or closed, essentially? Have you updated your thinking since you wrote that piece a month ago?
JOSEPH ALLEN: No, I think the piece reflects updated thinking. And I wrote the piece at the time when we knew the new variant, particularly the one discovered in the UK, was more highly transmissible and seemed very clear to me that it was already in the US and would if the same progression happened as we saw in the UK and elsewhere now that this would become the dominant strain. So there hasn’t been any new information really since I wrote that in terms of our understanding of this variant, it’s more highly transmissible, and that means we just need good controls in place. The point of that piece in late December was that it was a renewed call that schools needed to put in these controls that we’ve been talking about since June.
And so many schools didn’t do this through the summer, and many didn’t do it through the fall. And it was urging schools and I’m working with schools to say use the time over winter break knowing that this new variant is coming to put in these controls, if you haven’t done so already. And it gets back to my comment earlier in this, and we first gathered maybe about 40 minutes ago. That for schools that didn’t have these controls in place, if they didn’t have cases, it’s possible they just got lucky. Either it was a time when there were fewer lower levels of community spread and the last you know, the existing dominant strain was certainly highly transmissible, but not as highly transmissible as these new ones. So the margin for error disappears with a new highly transmissible variant. The good thing is that the controls we’ve been talking about are sufficient and should have been in place for a long time. They’re the same ones that were using in health care in terms of ventilation, filtration and better masks. So if adults are in particular because they’re higher risk, our concern, I’d say the only control change or the control that I would recommend enhancing is moving to better masks. This both protects others from the lower emission rates and also a better protection for the individual wearing the mask. So that’s really, I feel good about the controls we were seeing since the summer because they’re protective. And the basic fundamental physics around what we’re talking about here don’t change with the variant. Right. It’s more highly transmissible. We don’t quite know exactly why that is greater viral load, longer duration of infectivity changes and how it binds the receptors. But it also doesn’t matter for what I’m talking about in terms of controls, because the virus, the fundamentals of the virus haven’t changed in that it still moves through the air in respiratory aerosols and the techniques we’re talking about are effective against. The basic physics don’t change of how to capture or remove particles in the air that are carrying the virus, even if the virus is more infectious.
Q: Just one last follow-up question, and that is, how do you feel about hybrid education? Because I saw that you addressed that very briefly in your opinion piece in The Washington Post. I just wanted to hear your thoughts on school districts that are electing to go the hybrid, because many are.
JOSEPH ALLEN: Yeah, let me take a step back, too, and talk about exposure and risk, because very often, we get very narrow and talk about exposure in the classroom, but the reason schools need to be open is because the costs are of kids out of school are devastating and they are accruing and we’re just starting to see the reports roll out everything from mental health, virtual dropouts, decreases in literacy gains, issues around food security. And we’re going to see these reports for months and years, if not decades. And so it’s imperative that the country, we prioritize reopening schools. It’s unfathomable that we’re approaching one year when millions of kids out of school as a scary prospect. And so taking a step back, we need to prioritize the opening of schools, much like the new CDC director said. And I agree with saying the same thing. Schools should be the last to close and the first to reopen. And so it’s shocking to see in some places, bars and restaurants being reopened, underwater, parks being open, but schools not. This is really a problem. We’ve so deep prioritized our kids and schools and we know what to do to keep both kids and adults safe in school. So that relates to the hybrid question, which I’ve always felt was through the summer. It was this kind of amorphous place between fully closed and fully open that gave people a lot of comfort, despite it being really poorly defined, a different state to state, city to city and even neighboring district to neighboring school district without a real pause to think about what that might actually mean for exposure and risk. And a colleague, Bill Schneider, wrote about this eloquently, I thought in August, which is the piece I linked to in my current piece, talking about how hybrid models can actually increase exposure and risk. So we know if you look at the full body of evidence on schools, schools can be very safe. In fact, the levels in incidence of cases in schools in the recent report by CDC was lower than in the community. So when we go to a hybrid model, there’s been a faulty assumption that kids, if they’re not in school, then they’re home and there’s absolutely no exposure happening and we know that’s not the case. Parents are creating their own pods. Kids are going can have wider social networks. And so this can lead to greater exposure.
This is also, this is the reason we need to have kids back in school, because these are places where the protocols can be strictly followed. You start to see things right now where, let’s say schools aren’t providing after school activities, they’re shortening the day. But that doesn’t mean kids aren’t pursuing these things. This is happening all over the place with kids involved in club activities. And now that you’re mixing with wider social networks outside of the classroom, across districts, across town, sometimes even across states, as kids go to tournaments and things like this for sports. And so, in my view, would be much better to have the kids in a controlled environment in school where the controls can be implemented and enforced even for after school activities, including, as we think about the spring, you know, springtime sport activities outside, we’d be better having these associated with the school than what’s happening right now, which is, you know, kids and parents are finding other outlets. Parents are working, are bringing their kids to school. Sometimes kids are home without parents at home. So the hybrid model, in my view, hasn’t really been fully vetted. In terms of the question of does it really reduce exposure risk to individuals of the community. And I agree with the op-ed from August on this.
Q: Thank you.
MODERATOR: That’s all the time. Any final thoughts for us before we wrap up the call?
JOSEPH ALLEN: No, I appreciate all the comments and questions and actually was a nice group because we got to dive deeper into some of these topics. I appreciate that. Thank you.
This concludes the February 1st press conference.