Click for Part 1 and Part 2 of this series.

To recap: The Cooper administration sent a list of 22 studies, all published this year, containing what they state is “overwhelming” “scientific evidence for the protective effect of face masks and respiratory virus infection in healthcare and community settings.”

Remember: Gov. Roy Cooper issued orders against the normal scope of the Emergency Management Act, and Cooper has forced face masks on North Carolinians, even in their own homes at times, at the threat of misdemeanor charges, civil fines, business closures, people being turned away at business doors, people being threatened with trespassing, people being urged by the governor to call the cops on their fellow citizens, and perhaps worse.

So what this document, which is not easy to find through searching the DHHS web site independently, should contain is no less than this: a slam-dunk case justifying Cooper’s extreme, open-ended emergency orders.

This series will examine and discuss each study provided here by the Cooper administration, in the order it is presented by the Cooper administration, and ask whether it supports Cooper’s extreme exercise of power, because that is the relevant standard.

Here is the third and final batch:

Lyu and Wehby

Community Use of Face Masks And COVID-19: Evidence From A Natural Experiment Of State Mandates In The US. Health Affairs (2020).

Published on August 20 but with a “Fast Track Ahead of Print Version” posted much earlier, this study is very important to the Cooper administration. Cooper cited it first among the five “examples of studies studying the effectiveness of face coverings” that he included in his Nov. 23 executive order tightening his mask order against people. It was among the three presented before the General Assembly by state health bureaucrat Mandy Cohen on June 17, a week before Cooper first leveled his mask order against people. In August I wrote about that study in the context of North Carolina.

Lyu and Wehby identified 15 states and DC with executive orders or directives issued between April 8 and May 15 that mandate mask-wearing. They used the preceding five days before announcing the mask mandates as the baseline period for the trends in those states in order to build a predictive model for cases numbers if those states did not mandate mask-wearing. They then compared the differences in actual case numbers with the predicted, no-mask case numbers and estimated “daily case rate declines by 0.9, 1.1, 1.4, 1.7, and 2.0 percentage-points within 1-5, 6-10, 11-15, and 16-20, and 21+ days after signing [the mask orders], respectively.” From that they declare, “The main model estimates suggest that as many as 230,000–450,000 cases may have been averted due to these mandates by May 22.”

Note how Lyu and Wehby hedge such a bold-sounding finding. It’s based on their own model, the upper-bound estimates (“as many as”) range widely, and the estimates suggest that cases may have been averted. Lyu and Wehby themselves add that, “Estimates of averted cases should be viewed cautiously and only as general approximations.”

They found that the effects of the mask orders were larger when measured from the dates they were announced and signed, rather than the dates they took effect (typically 2-3 days later), which they said suggested “earlier compliance.” They also state that their “estimates suggest increasing effectiveness and benefits from these mandates over time.”

Time has not been as impressed with those estimates’ suggestions as Cooper has. Lyu and Wehby’s early-mandate states’ graphs (and North Carolina’s) are not showing evidence of “increasing effectiveness over time.”

Lyu and Wehby include an interesting side finding regarding governments ordering employers to mandate mask-wearing among employees: “We find no evidence for effects of states mandating employee face mask use.” They posit that it’s because “many businesses have been requiring their employees to wear masks” without a government order. Rather than conclude that such an order is redundant, however, they say it “may be reinforcing what many businesses are already choosing to do.”

Lyu and Wehby conclude with a might: “requiring use of face masks in public might help in reducing COVID-19 spread.”

Does this study support Cooper’s extreme exercise of power?


Probable effects (estimates “suggest,” “may have been,” “might” reduce, etc.) are insufficient for extreme emergency orders. Studies with model predictions of effects “over time” that turn out to be increasingly elusive over time are no basis for extreme emergency orders, especially not over time.

Estimates that should be “viewed cautiously” cannot be the basis of extreme emergency orders.

Eikenberry et al.

To mask or not to mask: Modeling the potential for face mask use by the general public to curtail the COVID-19 pandemic. Infect Dis Model (2020);5:293-308.

Received on April 6, 2020, this study builds a mathematical model for “assessing the community-wide impact of mask use by the general, asymptomatic public, a portion of which may be asymptomatically infectious.” Eikenberry et al. note from the outset that “Mask use in public spaces has been controversial in the US” but “far more prevalent in many Asian countries.” They project that an 80 percent adoption of wearing “moderately effective” masks “could prevent” some range of projected deaths in Washington and New York. They cite a great amount of uncertainty in the research literature about the effectiveness of masks, especially the cloth masks as required by Cooper’s order, but despite it all they write:

In summary, the benefit to routine face mask use by the general public during the COVID-19 pandemic remains uncertain, but our initial mathematical modeling work suggests a possible strong potential benefit to near universal adoption of even weakly effective homemade masks that may synergize with, not replace, other control and mitigation measures.

In one sentence, Eikenberry et al. balance “remains uncertain” with “suggests,” “possible,” “potential,” and “may” — according to their model.

About that uncertainty: they note that homemade masks “may” afford “significant, although variable and generally lesser, protection” than medical-grade masks; that “a range of masks provide at least some protective value”; that “It is largely unknown to what degree homemade masks … may protect against droplets/aerosols and viral transmission”; that an experiment “suggest[s] that while homemade masks were less effective than surgical masks, they were markedly superior to no mask”; and that a clinical trial “showed relatively poor performance for cloth masks relative to medical masks.”

Eikenberry et al. later refer again to “appreciable uncertainty.” Their modeling framework finds little possible effect from masks alone, which leads them to argue for masks as a complement to other public health control measures.

There is so much uncertainty. Eikenberry et al. write:

Our theoretical results still must be interpreted with caution owing to a combination of potentially high rates of noncompliance with mask use in the community, uncertainty with respect to the intrinsic effectiveness of (especially homemade) masks at blocking respiratory droplets and/or aerosols, and even surprising amounts of uncertainty regarding the basic mechanisms for respiratory infection transmission.

Beset with so much uncertainty, the authors resort to the Precautionary Principle for promoting “nearly universal” mask adoption: “Despite uncertainty, the potential for benefit, the lack of obvious harm, and the precautionary principle lead us to strongly recommend as close to universal (homemade, unless medical masks can be used without diverting healthcare supply) mask use by the general public as possible.”

Does this study support Cooper’s extreme exercise of power?


Regardless of how desirable a policymaker may view a particular action, a mathematical model’s “theoretical results” with so much admitted “uncertainty” surrounding them that they should be “interpreted with caution” can never be sufficient for extreme emergency orders. Such orders are the cardinal opposite of interpreting with caution.

It should also be self-evident that the Precautionary Principle is no basis for extreme emergency orders.

Ma QX, Shan H, Zhang HL, Li GM, Yang RM, Chen JM.

Potential utilities of mask-wearing and instant hand hygiene for fighting SARS-CoV-2. J Med Virol (2020).

Received on March 22, 2020, this study crafts experiments to test handwashing and mask-wearing as ways to slow the spread of COVID-19. For the mask-wearing, Ma et al. tested diluted avian influenza virus produced into aerosols by a nebulizer and “breathed” in a bag by an open-ended syringe through different mask materials. From that setup, they found that “N95 masks blocked nearly all the mock virus, and medical masks blocked approximately 97% of the virus, and the homemade masks blocked approximately 95% of the virus.”

This impressive-seeming finding requires, however, “homemade masks made of four-layer kitchen paper (each layer contains three thin layers) and one layer of polyester cloth,” which they say “should be helpful, as indicated by this study.” What shouldn’t be helpful, then? Ma et al. write:

Other types of homemade masks, especially those made of cloth alone, may be unable to block the virus and thus confer no protection against the virus.

Despite that, Ma et al. take a dim view of randomized controlled trials (RCTs) because they cast serious doubt on the possible effectiveness of even medical masks and don’t lend interpretation for cultural change. They write,

Some randomized controlled trials (RCTs) did not support the efficacy of medical masks because medical masks could not reduce infection rates of some viral respiratory diseases. Consequently, people in some countries opposed to using medical masks on common social occasions.

They state “the conclusions of these RCTs could be erroneous” based on their “assumed scenario” of a medical mask blocking seven out of 10 infection opportunities in a month. They therefore recommend that “common people should wear effective masks and bring an appropriate item for instant hand hygiene when needed.”

With respect to “some countries,” they contrast “China, Republic of Korea, and Japan, where mask-wearing is widely accepted and instant hand hygiene are usually accessible in public areas” with “Iran, Italy, Spain, and the USA,” where “many people in those countries are reluctant to wear medical masks” and that “None of those countries have decelerated the spread of the coronavirus so far.”

Does this study support Cooper’s extreme exercise of power?


This study’s mask results rely on how well the experiment of syringes “breathing” nebulized bird flu in a bag models real-life, possibly infectious exposure scenarios of COVID-19. While strongly supportive of N95 masks, medical masks, and masks of essentially 12 interior layers of fabric, Ma et al. suggest that other homemade masks “confer no protection against the virus.” That finding is exceedingly problematic, given that Cooper’s orders specifically exclude N95 respirators and surgical masks for the general public and require “face coverings” that could be almost anything: “synthetic and natural fabrics, including cotton silk, or linen … factory-made, sewn by hand, or can be improvised from household items such as scarfs, bandanas t-shirts, sweatshirts, or towels.”

A finding of no protection cannot be the basis of an extreme emergency order.

Furthermore, changing the culture is no business of an extreme emergency order.

Leung, N.H.L., Chu, D.K.W., Shiu, E.Y.C. et al.

Respiratory virus shedding in exhaled breath and efficacy of face masks. Nat Med 26, 676–680 (2020).

Published in May 2020, this study tested the effectiveness of surgical face masks on symptomatic people infected with the human (seasonal) coronavirus, influenza, or the common cold (rhinovirus) in preventing viral shedding. Test subjects were randomized to wearing or not wearing surgical face masks while providing samples of exhaled breaths. Leung et al. report that their “results indicate that surgical face masks could prevent transmission of human coronaviruses and influenza viruses from symptomatic individuals.”

Leung et al.’s results of the efficacy of the masks against the different viruses were mostly not significant, however. Surgical face masks did significantly reducing viral shedding of influenza droplets and seasonal coronavirus aerosol particles.

Leung write that their findings “might imply that close contact would be required for transmission to occur, even if transmission was primarily via aerosols, as has been described for rhinovirus colds.”

They acknowledge two major limitations to their study. One is “the large proportion of participants with undetected viral shedding in exhaled breath for each of the viruses studied.” But not only was it hard to detect viral shedding through exhaled breath; Leung et al. did not attempt to culture any shed virus to see if it was actual viable, writing “we did not confirm the infectivity of coronavirus or rhinovirus detected in exhaled breath.”

Does this study support Cooper’s extreme exercise of power?


This study concerned surgical masks, not the cloth to homemade “face coverings” that Cooper’s orders mandate for the general public. Beyond that, it specifically concerns (surgical) mask-wearing by symptomatic individuals, and finds a “major limitation” to be the fact that they couldn’t detect viral shedding from a “large proportion of” these symptomatic individuals in exhaled breath.

Cooper’s orders forces cloth to homemade masks on everyone on the assumption that everyone is a risk to others by virtue of simply breathing — especially if they show no sign of even being sick.

This study is too limited to apply to an extreme emergency order. Not only that, but Cooper’s orders do not apply to the findings of this study.

Fischer et al.

Low-cost measurement of face mask efficacy for filtering expelled droplets during speech. Science Advances (2020).

Submitted June 12, 2020, this study tests “14 commonly available masks or mask alternatives, one patch of mask material, and a professionally fit-tested N95 mask.” The masks are tested using an operator wearing a face mask and saying “Stay healthy, people” five times in the direction of a laser beam. As the speaker’s emitted droplets scatter light, it is recorded by a standard cell phone camera. “This experimental setup is simple and can easily be built and operated by nonexperts,” according to Fischer et al.

That is an important key because this study is not about determining what face masks governments should mandate. It is to test out a method for evaluating face masks given such government mandates. Fischer et al. write that theirs is not a “comprehensive survey of all possible mask designs” nor a “systematic study of all use cases.” Instead, they note, “We merely demonstrated our method on a variety of commonly available masks and mask alternatives with one speaker, and a subset of these masks were tested with four speakers.” These were, they write, “limited demonstration studies.” And from this perspective, “our measurements provide a quick and cost-effective way to estimate the efficacy of masks for retaining droplets emitted during speech for droplet sizes larger than 5µm.”

The reason for the study is that,

Mandates for mask use in public during the recent coronavirus diseases 2019 (COVID-19) pandemic, worsened by global shortage of commercial supplies, have led to widespread use of homemade masks and mask alternatives. It is assumed that wearing such masks reduces the likelihood for an infected person to spread the disease, but many of these mask designs have not been tested in practice.

In other words, this study begins with the assumption of a mask mandate and widespread use of homemade masks. Fischer et al. are interested in addressing the need for simple and nonexpert methods of testing mask efficacy.

Through their limited demonstration studies, Fischer et al. observe a wide range in mask efficacy, with some offering droplet reduction (as measured via cell phone camera) near that of N95 and surgical masks, but some others being close to not wearing a mask at all (neck gaiters seemed to disperse droplets into smaller droplets, for example).

Does this study support Cooper’s extreme exercise of power?


Taking a study that starts by assuming a mask order in place cannot justify a mask order. Circular reasoning is no basis for an extreme emergency order.

Going further, this study offers “limited demonstration studies” to find simple ways for nonexperts to test mask efficacy. None of that makes it appropriate for use to justify an extreme emergency order.

Bae et al.

Effectiveness of Surgical and Cotton Masks in Blocking SARS–CoV-2: A Controlled Comparison in 4 Patients. Annal of Internal Medicine (2020).

Published online on April 6, 2020, this article was retracted. See the Notice of Retraction here.

Does this study support Cooper’s extreme exercise of power?


A retracted article must never serve as the basis of an extreme emergency order.

Konda A, Prakash A, Moss GA, Schmoldt M, Grant GD, Guha S.

Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks. ACS Nano (2020)14(5):6339-6347.

Received April 18, 2020, this study tests the aerosol filtration of various fabrics that are used for cloth masks given the pandemic-driven “significant demand” for face masks , including “cloth masks, many of them homemade.” Konda et al. test the fabrics by using a generator that creates aerosol particles and using a blower fan to draw air through containing the particles. They tested “over 15 natural and synthetic fabrics that included materials such as cotton with different thread counts, silk, flannel, and chiffon,” “a N95 respirator and surgical masks” for comparison, and also “multiple layers of a single fabric or a combination of multiple fabrics for hybrid cloth masks.”

Konda et al. found a wide range in filtration efficiencies for the various fabrics, “rang[ing] from 5 to 80% and 5 to 95% for particle sizes of <300 nm and >300 nm, respectively.” Hybrids had the higher efficiencies, which the authors attributed to “a combined effect of mechanical and electrostatic-based filtration.” Multiple layers and cotton with high thread counts were also more effective. Given such a broad range, they summarize with can and potentially, that “cloth masks can potentially provide significant protection against transmission of particles in the aerosol size range.”

Also qualifying their findings: Konda et al. find masks lost most of their effectiveness if there were “gaps (as caused by an improper fit of the mask),” which “can result in over a 60% decrease in the filtration efficiency.”

This issue of gaps and “leakage” matter to their findings. “It is important to note,” they write, “that in the realistic situation of masks worn on the face without elastomeric gasket fittings (such as the commonly available cloth and surgical masks), the presence of gaps between the mask and facial contours will result in ‘leakage’ reducing the effectiveness of the masks. It is well recognized that the ‘fit‘ is a critical aspect of a high-performance mask.” They later reiterate the problem of “air leaks that arise due to improper ‘fit'” and it being “critically important” for mask design to take mask fit into account.

There is nothing in the study about government officials ordering mask-wearing, regardless of type and filtration efficiency. The authors do foresee “Opportunities for future studies,” such as “cloth mask design for better ‘fit'” as well as “the role of factors such as humidity (arising from exhalation) and the role of repeated use and washing of cloth masks.” (Other studies put forward by the Cooper administration have warned against the dangers of masks becoming moist from exhalation due to long use or in physical activities or exercise.)

Does this study support Cooper’s extreme exercise of power?


Probable effects (“can” “potentially” provide) of mask efficiency with such wide ranges (“5 to 95%” that could be cut by 60% depending on fit) cannot be the basis for extreme emergency orders.

This study was about testing mask filtration efficiency, not about calling for restrictive government policy. If Cooper were to recommend mask wearing rather than force them on people and have it policed by local law enforcement and citizen informants, such a study could be used to inform their choices. Cooper’s order, however, even expressly mentions using towels for homemade masks.

Cooper still has — and has always had — the option to treat North Carolinians as free-thinking adults and use his office and state health department “to recommend, to persuade, even to urge people to adopt practices such as wearing face coverings that they believe is healthy.” Instead, he has repeatedly resorted to issuing extreme emergency orders. Cooper’s own science doesn’t support going to those extremes.

Bonus study: Hatzius et al.

Face Masks and GDP. Goldman Sachs Research

Published June 29, 2020, this study was not included in the Cooper administration’s list. It is, however, one of the five “examples of studies studying the effectiveness of face coverings” that Cooper cited in his executive order tightening face mask restrictions against people.

Writing for Goldman Sachs, Hatzius et al. are keenly interested in avoiding government lockdowns, such as what Cooper instituted in his “Stay-At-Home” executive order of March 27 and what Cooper is flirting with reinstituting with his most recent “Modified Stay-At-Home” order of December 8. They acknowledge that “investors … worry about renewed broad lockdowns with large negative effects on GDP.”

Hatzius et al. see that “many European countries now have national mask mandates in place,” and also that “much of East Asia has strong social norms of mask wearing when sick and during pandemics. They wonder, “How effective would a national mandate be in pushing mask usage to Southern European or East Asian levels?” They therefore seek to ask three questions about whether the U.S. should have a national mask order to begin their analysis:

First, how effective is a face mask mandate in increasing face mask usage? Second, does increased face mask usage lower virus transmission, and if so by how much? And third, how economically valuable is a face mask mandate in terms of reducing the need for broad lockdowns with their well-documented negative effects on GDP?

Using Lyu and Wehby’s findings (see the first study cited here, above), they “estimate … that a national mandate could raise the percentage of people who wear masks by 15 pp [percentage points] and cut the daily growth rate of confirmed cases by 1.0 pp to 0.6%.” From that they argue the following:

These calculations imply that a face mask mandate could potentially substitute for lockdowns that would otherwise subtract nearly 5% from GDP.

Hatzius et al. repeated mention the mask mandate as a “substitute” for lockdowns, because lockdowns would “hit GDP”/”subtract nearly 5% from GDP.”

Does this study support Cooper’s extreme exercise of power?


The assumptions behind this study come from Lyu and Wehby, which as discussed above rely on probable estimates based on their model’s predictions of effects “over time,” which over time have proven elusive. Lyu and Wehby also cautioned that their estimates should be “viewed cautiously.” Running with a different study that doesn’t view those findings cautiously cannot be the basis of extreme emergency orders.

Furthermore, Hatzius et al. also rely on probable effects (calculations “imply,” mandate “could” “potentially” substitute), with respect to a national mask order. None of that can justify an extreme emergency state order.

Changing the culture to “push” North Carolinians to adopt “social norms” of other cultures is no business of extreme emergency orders.

If we allow that their implied possible effects of a mask order would apply to a state, and that it could potentially keep a governor from locking down the economy again (and thereby restrain himself from doing serious damage to state GDP), shouldn’t Cooper be sobered by their warnings about economic damage from lockdowns? Instead, the governor flat-out warned of returning to lockdowns in announcing the very order that cited this research, and he has continued to do so ever since, warning “We’ll do more” even after dropping the latest curfew/modified stay-at-home order.

Click for Part 1 and Part 2 of this series.