For the tenth day of mask mess, we got these:

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 virusand 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.

Click for more of the Twelve Days of Mask Mess series.