Suggestions for Comfortable and Effective Face Masks, e.g., Korean KF94’s

With Covid cases and deaths surging despite widespread vaccinations, face masks are back in. Back in the dark days of early-mid 2020, all commercial masks of any kind were allocated to medics/first responders. Back then, the only mask option for the rest of us was to cobble together something made of regular cloth. But studies I looked at show that the protective performance of those cloth masks, and even standard rectangular surgical masks, is really quite poor [1].

A cloth or surgical mask is definitely better than nothing, but is much inferior to other mask options which are now widely available. If you are going to bother with a mask at all, why not use a more effective one? A well-known effective mask is the KN-95. It has a kind of aggressive beak-like profile, as shown below, and typically uses elastic earloops. It gives good protection because it seals to the face (including around the nose, thanks to a malleable metal strip there) and is made of appropriate multi-layer filter materials. It is the standard protective respiratory mask in China, whereas in the U.S. the standard protective mask is an N95, with elastic straps that go around the whole head, not the ears.

Image Source: Amazon

I got a box of ten KF95’s back in June of 2020. I loved them – they were comfortable, worked OK with my glasses, and clearly sealed well to my face. However, I gave some of these away to family members, lost a few, and used the rest so many times so they started to lose their shapes.

There are lots of KN95’s for sale on Amazon, all made in China. Not all of these may be of the same quality. Some but not all of these brands were tested and approved by the FDA for emergency use; this article from March 2021 notes some of these brands that were for sale on Amazon at that time. It seems the approved Powecom masks are still for sale.

A problem with most of these Amazon KN95’s is that the earloops are painfully tight around the ears. I pored over the comments to try to select masks where at least some of the reviewers claimed the masks didn’t hurt. Alas, all my KF95’s are pretty much unbearable for a guy like me with maybe an oversized head. (I compared the length of their earloops with my original comfortable KF95, and indeed the earloops are clearly shorter on all the new ones).

In the course of reading dozens of reviews of KN95 masks, I saw several comments recommending KF94 masks instead. These are made in South Korea. They are standard personal protective equipment in that country, and as such must meet certain standards for fine particle capture. They look a little different than most masks, but seem less beak-like than the KN95s. They have a flattish rectangular middle part which is the main filter, with two triangular sections that cover the nose and the chin:

Image: Amazon

So I got a box of KF94’s, large size, and they are wonderfully comfortable for me. No stress on the ears, and sealing over the whole face. The shape of the mask keeps it from rubbing on your mouth. The “Large” size I got was actually a tiny bit looser than felt optimal, so I tied tiny knots in the lower part of the earloops to shorten them a bit. My wife uses a mask extender strap (e.g., HX AURIZE Mask Extender Strap on Amazon) around the back of her head to pull the KF94 earloops a little tighter, with the added benefit that if she wants to take the mask off temporarily, it can hang around her neck via the extender strap. In sum, the KF94s are a win, and I highly recommend them.

I see on Amazon that small (for e.g. 7-12 year old children) and medium KF94 masks are also available. One caveat on buying is to make sure that you are buying from an actual Korean seller, else you risk getting an inferior Chinese knockoff.

Back to my unusable KN95’s. I know that you can use mask extender straps like the HX Aurize straps linked above, or similar homemade hacks, to go behind your head and take some of the direct pressure off the back of the ears. However, I found using a behind-the-head strap still put pressure on part of my ears, and was just an added complication. I thought, surely there must be some way to make those darned earloops simply longer. What I did for one mask was to cut the earloops close to the bottom of the mask, and tie in a small rubber band into each loop, to make them effectively longer. (I put a dab of glue on the cut ends of the earloops, to keep them from unravelling). That worked out well, so I can recommend this as a “hack”. I also see on Amazon that you can order ¼” wide white elastic ear loop type band material, and I think I will buy some. I can then take more of my tight KN95 masks, cut the existing earloops, and tie in an extra inch or two of this elastic to get the length right for my head size.

ENDNOTE

[1] Some studies on masks:

(A) https://pubmed.ncbi.nlm.nih.gov/32845196/  Kim, et al. 2020. They had seven Covid-inflected patients cough five times with various masks on, and with petri dish sitting in front of them to catch germs. A surgical mask did no better than no mask at all (3 out of 7 patients’ petri dishes got infected in both cases), whereas zero out of 7 patients’ petri dishes got infected for a full N95 respirator made by 3M (not a Chinese KN95) or for a Korean-made KF94 mask.

(B) https://www.acpjournals.org/doi/10.7326/M20-6817   Bundgaard, et al., 2020. Done in Denmark around April-June 2020. From 6000 participants, all of whom initially tested Covid-negative, half were randomly selected to wear standard surgical-type masks while in public and half to not wear masks. (These are the usual rectangular masks that do not seal tightly to the face). Incidence of Covid infection after about a month was assessed for each group. For mask-wearers, the infection rate was about 1.8% versus 2.1% for the non-masked group. According to the standard statistical definitions, this was not enough to show that wearing that type of mask gave significant protection against becoming infected. That said, the difference between the 1.8% and the 2.1% is compatible with a 46% reduction to a 23% increase in infection on 95% confidence intervals. Depending on how you want to slice the numbers, it seems fair to say that there may have been “some” effect of the masks here. Also, it should be noted that this study did not test whether wearing a surgical mask would help keep an infected person from spreading the disease (I suspect the answer to that would be “yes, sort of”).

(C) https://pubmed.ncbi.nlm.nih.gov/33087517/ Ueki, et al., 2020. They used two full size human mannequin heads, and tied masks on their faces. The “Spreader” head was piped to have a stream of covid-aerosol-laden air coming out of its mouth. The “Receiver” head had a pipe that pulled air in through its mouth and through a gelatin membrane filter to collect the covid viruses that made it through the masks. Some of the results are shown below. I am not sure how to summarize them accurately in a few words. Note that these plots are on log scales, so small visual differences in the bars are actually big (see the numbers at the bottom of the bars). It seems clear that the cloth (cotton) and the surgical masks blocked some virus spreading compared to no masks, but a full N95 mask was much more effective (the N95 was tested with its edges naturally resting on the contours of the mannequin face, and also “fit” with the edges sealed against the face with adhesive tape). A KN95 or KF94 mask was not tested here.

POSTSCRIPT

After publishing this POST, I noted Jeremy Horpedahl’s post from last week, suggesting that the costs of wearing masks may be worth it even if they give a 10-15% decrease in viral incidence. Jeremy referenced an article by Bryan Caplan who questions the trade-offs with wearing masks having only marginal effectiveness vs. the discomfort and the dehumanization of having people’s faces obscured. Caplan in turn referenced a survey of research by Jeffrey Anderson (August, 2020) which summarized many real-life randomized controlled trials with populations wearing/not-wearing masks (presumably the surgical kind, not N95/KN95/KF94 better-sealing types) which found generally no benefit to wearing these types of  masks in reducing the incidence of virus transmission. (These studies were mainly pre-Covid, dealing with SARS and other viruses). This overall result is roughly consistent with the Danish study mentioned above, which did not find a significant difference for using those types of masks to protect from viral infections.

Delta: Danger is Rising, but 2021 is not 2020

Covid cases are rising rapidly in the US thanks to the more contagious delta variant.

Based on the experience of 2020, this has many states, cities, and organizations considering a return to mask mandates and shutdowns. But our situation in the US has changed substantially since 2020 as we now have better knowledge, better masks, and above all abundant vaccines.

We can see this difference clearly when looking at countries hit by the Delta wave before us. It first devastated India, where less than 10% of the population was fully vaccinated, officially killing 400,000 people and unofficially perhaps 10 times that. In constrast the UK, where more than half the population was fully vaccinated, saw a major spike in cases that did not translate into a major spike in deaths:

The delta waves seem to come and go quickly, with cases rising more rapidly than previous waves, but also falling rapidly 6-8 weeks after they began to rise in India, the UK, and the Netherlands. Cases began rising in the US at the beginning of July, so if this pattern holds we have about 2-4 more weeks of rising cases before a rapid drop.

My worry is that a spike in cases just before the school year will lead schools to shut down just as the danger begins to recede, and when vaccines mean the danger was never as great as in previous waves. Externality-based arguments for shutdowns and mask mandates are now substantially less valid than in 2020 but I don’t know that policymakers have internalized this. The Biden admin actually does seem to get it, calling this a “pandemic of the unvaccinated“- i.e., if you’re worried, get vaccinated, and if other people don’t, that’s their problem. Even with delta the vaccines reduce covid’s danger to you by ~10x, and so also reduce the protection you gain from controlling others by ~10x.

The situation with masks has also changed. Cloth masks have limited effectiveness in protecting you from others, but decent effectiveness in protecting others from you, which meant there was a strong externality-based case for mask mandates. But now in 2021 high-quality KN-95 and even N-95 masks are easily available, and unlike cloth masks they offer excellent protection FROM others, as well as FOR others. Anyone who is vaccinated and wearing an N-95 really has nothing to worry about anymore, and little reason to force masks onto others.

The main externality-based arguments that could still work are for vaccine mandates and for restrictions in areas where hospitals are overwhelmed by unvaccinated Covid patients in a way that substantially worsens care for non-Covid patients. But outside of areas with low vaccination rates leading to overwhelmed hospitals, I no longer see a good case to impose mask requirements or restrictions on movement or events.

According to one set of projections, by the end of August adult ICUs (though not hospitals overall) will be over capacity in most low-vaccination states:

If you want to wear a mask and avoid crowds, you can, and in fact probably should do at least one of those during the Delta wave of the next month. But the externality-based case for restrictions is mostly gone, and governments would do better to focus on continuing vaccine rollout in the US and ensuring vaccines are available worldwide to help other countries and to prevent more variants from emerging and finding their way here. Personally I’m glad that my employer has a vaccine mandate but, at least currently, no mask mandate. For those who do still want Covid restrictions I ask- what are you waiting for? What event or number would make you say “ok, now we can go back to normal”? When do you expect that to happen? For me, what I was waiting for was vaccines available for everyone and now, at least in the US, we are lucky to have that.

Why is the COVID Delta Variant So Infectious?

The “delta variant” of COVID-19 is far more virulent than the original strains, and is largely responsible for the recent surges in COVID cases in the U.S. and worldwide. Centers for Disease Control and Prevention Director Rochelle Walensky told the Senate on July 15  that the delta variant now makes up 83% of U.S. cases, up from 50% at the beginning of this month. It was first detected in India, then spread to the U.K. and the U.S., and around the world.

What is it that makes the delta variant so infectious? From a molecular point of view, here are the known functional mutations in the DNA that produces the “spike” proteins in the virus which bind to human cells:

Source: Stanford

Four of these mutations in particular are believed to contribute to the virulence of this strain, as discussed here. Among other things, they can cause the spike protein to bind more strongly to our cells, and inhibit our immune response. See here for 3-D model of the virus spike binding to human receptor, showing the locations of those mutated proteins.

As a result of those mutations the delta variant grows faster inside people’s respiratory tracts and reaches much higher levels. Per NPR,

On average, people infected with the delta variant had about 1,000 times more copies of the virus in their respiratory tracts than those infected with the original strain of the coronavirus, the study reported.

In addition, after someone catches the delta variant, the person likely becomes infectious sooner. On average, it took about four days for the delta variant to reach detectable levels inside a person, compared with six days for the original coronavirus variant.

… People who have contracted the delta variant are likely spreading the virus earlier in the course of their infection.

How can we stop it? It is pretty simple:  get vaccinated (or never be in a closed space with other unvaccinated humans). Vaccines don’t totally prevent you from getting COVID initially, so you might still have early symptoms and also be able to spread the virus to others for a few days. However, vaccines are highly effective in helping your immune system to quickly shut down any infection you do get before the symptoms get severe. This is true for all for essentially all strains of COVID, including delta.

Again per NPR,

Preliminary data shows that in some U.S. states, 99.5% of COVID-19 deaths in the past few months were among people who weren’t vaccinated, said CDC director Dr. Rochelle Walensky at a White House press conference in early July.

And 97% of those currently hospitalized with COVID-19 are unvaccinated, according to Walensky.

Just compare the two maps below of which American states have high/low vaccinations and high/low COVID incidence, and draw your own conclusions:

Percent Vaccinations. Image source: ABCnews

COVID Case Density. Image source: ABCnews

When will housing prices fall?

US housing prices shot up during the pandemic. People spending all day at home wanted bigger houses, and the Fed fueled their demand with low interest rates. But home owners didn’t want to sell- the total number of homes on the market is less than half what it was a year ago. This combination of rising demand & falling supply has sent prices way up & cut the time homes spend on the market.

Contrary to popular belief, its actually rare for economists to make market forecasts and most of us aren’t especially well-equipped to do so- but I’m going to try anyway! I think home prices will almost certainly stop growing so quickly, and may actually fall, within two years.

Why? The end of the pandemic, the rise of new construction, and the end of low interest rates.

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Covid Pandemic Diary Part 2

I pick up from my previous post in May 2020.

That tweet from early May captures some of the joys and frustrations of working from home with small children. It was hard to get work done. My career suffered. At the same time, in my case, there were happy moments. My kids got more time with me and also with each other. One reason I didn’t go crazy is that we could get outside and the weather was decent throughout “lockdown”.

Something that happened quietly is that two-income parents hired private nannies and never mentioned it on social media. I know there are lots of families who did not do that and had a hellish year trying to parent while working from home. In my case, daycare was back open in June with extra health precautions.

Late Spring was a time when it seemed like the United States might be the worst-performing country. Certain parts of Asia were models of efficiency and cooperation, by comparison.

Late May is when I breathlessly tweeted that I had purchased a box of masks. Finally, the supply caught up with demand. Masks became plentiful and cheap. That helped us find ways to be together without such a high chance of spreading germs.

July 2020 – My public school system (which had gone virtual in the Spring) announced that elementary parents would have a choice of in-person (with masks) or virtual for the Fall. Our schools have been open all year (with masks) and no major outbreaks.

High school and middle school students did more forced remote days than elementary-aged kids. I really appreciated the creativity and flexibility. Remote school is harder on younger kids (and parents of younger kids).

I emailed my city representative to ask for a drive-through testing site in our city. He said he would bring it up at the council meeting that night. Within two weeks, they had done it! This was incredible. I did not expect that because of one request this would suddenly just happen. I suppose there were enough people who wanted it already. It probably helped that city council elections were right around the corner and he could take credit for doing something helpful. Twice in 2020, I used my city hotline to get an appointment for a Covid test.  

In August, my university got ready to bring students back for some in-person classes, while also offering remote options for every class. The campus sprouted one-way walking stickers and masks were required everywhere.

Economists moved conferences online. On September 10, 2020 I stayed up a little late to catch one of my Chinese colleagues presenting at the ESA worldwide virtual conference. My daughter didn’t want to stay in bed, so I let her stare at the Zoom meeting for a bit.

I have said nothing so far about politics in 2020, the year of politics. The televised debate between President Trump and now-President Biden in September of 2020 was a stressful event for me. If we can’t even speak to each other, then no amount of good ideas will help us solve problems. That sad moment in American history made me more determined to maintain this blog as a place to talk about ideas.

The Fall of 2020 was when intellectual soldiers like Alex Tabarrok were alerting us to the fact that we could have vaccines if the government would let us. I was following that news and doing some signal-boosting. Some of my friends on social media announced that they were participating in vaccine trials – thanks!

My university offered rapid tests to employees at the end of the Fall semester. It almost felt like a miracle to be able to just know in 15 minutes if I was carrying Covid or not (yes, I know about the false negatives).

There were moments in peak-wave when local hospitals were full because of Covid. Alabama’s worst month as measured by deaths was January 2021. When Covid was spreading widely in December 2020, I believe a lot of people did not expect that vaccines would be available so soon in the future. On the margin, a few more people might have foregone holiday parties if they had known.

Vaccines became available to medical professionals around January 2021. That was exciting news, since we had all been feeling bad about the doctors and nurses treating infectious Covid patients.

Earlier than I expected, I was able to get the Pfizer vaccine because of my “educator” status in the state of Alabama. It is convenient that I live near UAB hospitals. They had the technology for cold storage and administering the Pfizer vaccine. It was a huge relief to get the vaccine while teaching in-person classes. Since I had been following vaccine news closely, it felt like a huge achievement.

There was a period of time when conversation among my neighbors and colleagues revolved around the vaccine. Water cooler talk was “which one did you get?” or “did you have side effects?”  People told stories about how a friend called to tell them that one place had extra doses at the end of the day. Even when it was technically reserved for old people only, some young people found connections. One of my students told me he wouldn’t be in class because he was going to drive 6 hours to another state to get a vaccine. I don’t want to make the system sound corrupt, because it largely was not. It’s just a fact that some places couldn’t distribute all of their doses to the people who were designated for them. It was better to get the leftovers into arms than waste them.

I treasured that energy, and I miss it. Now, in May 2021, after all the work that went into producing vaccines, Americans are refusing to show up for shots.

Covid Pandemic Diary Part 1

Last week on Twitter, a writer in France reached out for accurate information about what is going on the US right now with regard to vaccines.

This got me thinking about the value of narratives and true stories. I’m going to chronicle a few of the Covid events experienced by me personally. Myself and the adults in my family are fully vaccinated, so life is starting to feel normal again, even though I still wear masks in many public places. I’d like to write this down in case it is useful and so that I don’t forget it.

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Blood Clots for You and Me

On April 13, 2021, CDC and FDA recommended a pause in the use of Johnson & Johnson’s Janssen COVID-19 Vaccine. When I first heard that the FDA was pausing the J&J vaccine because of less than 10 blood clots out of millions of patients, I thought I’d really get to the bottom of blood clots and blog about it. Other people (some of them are the kind of doctor that helps people) have already done a pretty good job in the past few days.

First, it is a tragedy that the vaccine is not being give to every male over 50 who wants it. Doing so would free up many thousands of other types of vaccines for young women.

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Teaching Economics with COVID

In many of my blog posts I address either issues related to COVID or teaching economics. In this post, I want to combine the two. One thing economists of a certain age struggle to do is find examples to illustrate economic concepts which will actually connect with 18-22 year olds. The silver lining of the pandemic is that we now have an example that everyone is familiar with, and can be used to illustrate a host of economic concepts.

A great new book by Ryan Bourne, Economics in One Virus, really pushes this idea to the limit. He uses examples related to COVID to explain almost every single concept you would cover in a typical introductory economics course: cost-benefit analysis, thinking on the margin, the role of prices, market incentives, political incentives, externalities, moral hazard, public choice issues, and more.

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Emily Oster on Vaccines in February 2021

My third post on Covid data heroes features Dr. Emily Oster. Emily is a mom. Lot’s of economists are moms, but few have incorporated it quite as much into their careers. Emily has written a book on pregnancy and a new one on what to do with the kids after they are born. She does a great job explaining scientific research in a way that is easy to understand.

Emily made a big push to collect data on schools and covid back when there was crippling uncertainty about how dangerous it is to let children go to school in person.

She has a great email newsletter and substack. Her latest post is called “Vaccines & Transmission Redux Redux”. In this post, she distills the latest research to give practical advice on when kids can see grandparents once the vaccines are out.

For a long time now, some families have been avoiding close contact with elderly relatives. When can we go back to normal?

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