I’d like to
think that most Americans still believe that truth exists, that truth can be
known, and that we make the best decisions when we have truthful
information. Science, especially “good science,” is one way of finding and publishing correct truth claims. However, in the era of COVID-19, it seems
there are many “middle people” operating between what science discovers and
what the average person reads or hears in the news. For example, there are scientific studies of
the efficacy of masks in preventing spread of viruses. Then, there are news reports recommending
whether or not we ought to wear masks.
What is the truth about masks?
The purpose of this article is not to convince you of whether or not to wear a mask. Instead, as I tried to do with an April article, (See COVID-19 Policies & Outcomes: Learning Online), my purpose here is to simply reference several scientific studies to show how researchers report their findings, make conclusions, and offer recommendations based on their results. In other words, I want to take us back to the primary sources, the journal articles from the scientific laboratories. These are the sources of information from which newspaper and TV journalists obtain their information. Resultant newsprint or media newscasts which most of us receive are considered secondary sources, and perhaps tertiary sources, any of which are subject to accidental or deliberate errors.
What follows are references to two primary (scientific journal) sources which report recent studies of the effectiveness of masks in intercepting COVID-19 and other viruses. I am also including one secondary source compiled by the World Health Organization (WHO) based primary sources. Each title is accompanied with the link so you can obtain the article in PDF format to read for yourself. I have given each source a handy label which I can use to refer to each article as follows:
1) Vietnam Study (2015)
MacIntyre CR, Seale H, Dung TC, et al. A cluster randomised trial of cloth masks compared with medical masks in healthcare workers. BMJ Open 2015;5: e006577. doi:10.1136/bmjopen-2014-006577
Locate Article: HERE
2) WHO Guidance Report
Advice on the use of masks in the context of COVID-19 -- WHO in April, 2020
Locate Article (automatic download of PDF): HERE
3) Nature Medicine study:
Leung, N.H.L., D. K. W. Chu, et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nature Medicine 26: 676–680, May 2020
Locate Article: HERE
Vietnam Study
The “Vietnam study” involved 1,607 hospital health care workers (age 18 or older) employed full-time in selected high-risk wards among 14 different hospitals. The objective of this study was “to compare the efficacy of cotton cloth masks to medical masks in hospital healthcare workers.” Their conclusions are as follows:
Caution against Cloth Masks: “This study is the first randomized critical trial of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection. Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for health care workers, particularly in high-risk situations, and guidelines need to be updated.”
The results of the “Vietnam study” were summarized in the adjacent graphic presented by the Laura Ingraham Angle on Fox News. This news channel is a secondary source that is seen by millions of viewers. The Fox News summary accurately presents the conclusions of the study. However, reading the journal article reveals several complicating factors that are typically missed in news reporting. The following excerpt from the journal article addresses some of the limitations of the study:
A limitation of this study is that we did not measure compliance with hand
hygiene, and the results reflect self-reported compliance, which may be subject
to recall or other types of bias. Another limitation of this study is the lack
of a no-mask control group and the high use of masks in the controls, which
makes interpretation of the results more difficult. In addition, the quality of
paper and cloth masks varies widely around the world, so the results may not be
generalisable to all settings (MacIntyre
C.R. et al, p. 7).
What can we take away from the “Vietnam Study?” First, the “Vietnam Study” appears to demonstrate “good science.” The researchers were objective, conducted experiments and analyzed data with care, tried to avoid bias, were careful not to overstate conclusions, and invited scrutiny and critical analysis by peers and readers.
Second, primary journal sources often contain admissions of limitations that may or may not affect the conclusions; and, usually suggest the need for additional scientific research. However, news reporting based on these primary sources often do not include these details. Therefore, I encourage readers to check out the “Vietnam Study” article itself to gain more of a sense of how science is conducted and reported.
Finally, the “Vietnam Study” provides much reason for us to question the efficacy of cotton cloth masks in preventing transmission of virus, and suggests that “moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection.” We ought to be asking, “Is it possible that by wearing a mask I am increasing my risk of infection?” How will this scientific study affect your choices, and the current policies of our state governors regarding masks?
WHO Guidance Report
Unlike the “Vietnam Study,” the “WHO Interim Guidance Report” is a secondary source with recommendations based on primary research reports. This secondary source by definition represents interpretations and recommendations made by at least some people who were not directly involved in primary research and reporting. However, if the interpretations and recommendations are accurate, the secondary source can reveal patterns and trends based on multiple research results including the “Vietnam Study” by MacIntyre CR, Seale H, Dung TC, et al. cited above.
The “WHO Guidance Report” offers the following summation concerning the
efficacy of wearing masks to prevent spread of COVID-19:
When infected people wear masks: “Studies of influenza, influenza-like illness, and human coronaviruses provide evidence that the use of a medical mask can prevent the spread of infectious droplets from an infected person to someone else and potential contamination of the environment by these droplets.”
When uninfected people wear masks: “There is limited evidence that wearing a medical mask by healthy individuals in the households or among contacts of a sick patient, or among attendees of mass gatherings may be beneficial as a preventive measure. However, there is currently no evidence that wearing a mask (whether medical or other types) by healthy persons in the wider community setting, including universal community masking, can prevent them from infection with respiratory viruses, including COVID-19 (WHO Interim Guidance Report, p. 1).”
This April, 2020 recommendation by WHO was consistent with the recommendation at the time from Dr. Anthony Fauci who informed Americans that “There’s no reason to be walking around with a mask. When you’re are in the middle of an outbreak, wearing a mask might make people feel a bit better, and it might even block a droplet, but it’s not providing the perfect protection that people think that it is.”
3) Nature Medicine study:
Leung, N.H.L., D. K. W. Chu, et al. Respiratory virus shedding in exhaled breath and efficacy of face masks. Nature Medicine 26: 676–680, May 2020
Locate Article: HERE
Vietnam Study
The “Vietnam study” involved 1,607 hospital health care workers (age 18 or older) employed full-time in selected high-risk wards among 14 different hospitals. The objective of this study was “to compare the efficacy of cotton cloth masks to medical masks in hospital healthcare workers.” Their conclusions are as follows:
Caution against Cloth Masks: “This study is the first randomized critical trial of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection. Further research is needed to inform the widespread use of cloth masks globally. However, as a precautionary measure, cloth masks should not be recommended for health care workers, particularly in high-risk situations, and guidelines need to be updated.”
The results of the “Vietnam study” were summarized in the adjacent graphic presented by the Laura Ingraham Angle on Fox News. This news channel is a secondary source that is seen by millions of viewers. The Fox News summary accurately presents the conclusions of the study. However, reading the journal article reveals several complicating factors that are typically missed in news reporting. The following excerpt from the journal article addresses some of the limitations of the study:
What can we take away from the “Vietnam Study?” First, the “Vietnam Study” appears to demonstrate “good science.” The researchers were objective, conducted experiments and analyzed data with care, tried to avoid bias, were careful not to overstate conclusions, and invited scrutiny and critical analysis by peers and readers.
Second, primary journal sources often contain admissions of limitations that may or may not affect the conclusions; and, usually suggest the need for additional scientific research. However, news reporting based on these primary sources often do not include these details. Therefore, I encourage readers to check out the “Vietnam Study” article itself to gain more of a sense of how science is conducted and reported.
Finally, the “Vietnam Study” provides much reason for us to question the efficacy of cotton cloth masks in preventing transmission of virus, and suggests that “moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection.” We ought to be asking, “Is it possible that by wearing a mask I am increasing my risk of infection?” How will this scientific study affect your choices, and the current policies of our state governors regarding masks?
WHO Guidance Report
Unlike the “Vietnam Study,” the “WHO Interim Guidance Report” is a secondary source with recommendations based on primary research reports. This secondary source by definition represents interpretations and recommendations made by at least some people who were not directly involved in primary research and reporting. However, if the interpretations and recommendations are accurate, the secondary source can reveal patterns and trends based on multiple research results including the “Vietnam Study” by MacIntyre CR, Seale H, Dung TC, et al. cited above.
When infected people wear masks: “Studies of influenza, influenza-like illness, and human coronaviruses provide evidence that the use of a medical mask can prevent the spread of infectious droplets from an infected person to someone else and potential contamination of the environment by these droplets.”
When uninfected people wear masks: “There is limited evidence that wearing a medical mask by healthy individuals in the households or among contacts of a sick patient, or among attendees of mass gatherings may be beneficial as a preventive measure. However, there is currently no evidence that wearing a mask (whether medical or other types) by healthy persons in the wider community setting, including universal community masking, can prevent them from infection with respiratory viruses, including COVID-19 (WHO Interim Guidance Report, p. 1).”
This April, 2020 recommendation by WHO was consistent with the recommendation at the time from Dr. Anthony Fauci who informed Americans that “There’s no reason to be walking around with a mask. When you’re are in the middle of an outbreak, wearing a mask might make people feel a bit better, and it might even block a droplet, but it’s not providing the perfect protection that people think that it is.”
Facebook now flags the April interview with Dr. Fauci as “false
information. Dr. Fauci later recommended
wearing of masks and explained that his turn-around was based on his concern
that if everyone wore a mask, healthcare workers would be left in short
supply. However, another April study,
this one published in Nature Medicine, seems to confirm Dr. Fauci’s
original recommendation against the need for wearing masks. Is it possible that Dr. Fauci was scientifically
correct in his April recommendation? Let’s
have a closer look at the “Nature Medicine Study.”
Nature Medicine Study
This report, published online April 3, 2020, is a primary source from a reputable journal. The study was conducted from March, 2013 through May, 2016 in a general outpatient clinic of a private hospital in Hong Kong. Researchers “screened 3,363 individuals in two study phases, ultimately enrolling 246 individuals who provided exhaled breath samples. Among these 246 participants, 122 (50%) participants were randomized to not wearing a face mask during the first exhaled breath collection and 124 (50%) participants were randomized to wearing a face mask. Overall, 49 (20%) voluntarily provided a second exhaled breath collection of the alternate type.”
Results of the “Nature Medicine Study” were summarized as follows:
Virus Transmission in Air: “Our results indicate that aerosol transmission is a potential mode of transmission for coronaviruses as well as influenza viruses and rhinoviruses.”
Efficacy of Masks: “Our findings indicate that surgical masks can efficaciously reduce the emission of influenza virus particles into the environment in respiratory droplets, but not in aerosols.”
Very Little Virus Shedding: “Among the samples collected without a face mask, we found that the majority of participants with influenza virus and coronavirus infection did not shed detectable virus in respiratory droplets or aerosols…”
The “Nature Medicine Study” affirms that coronaviruses can be transmitted in respiratory
droplets (size greater than 5 micrometers) and in aerosols (size =
less than 5 micrometers). Surgical face masks
(# 62356, Kimberly-Clark) reduced transmission of virus in respiratory droplets
but not virus transmission in the smaller aerosols. This result should be unsettling to infected
people who depend on mask wearing to reduce transmission to others, and even to
noninfected people who depend on masks to avoid infection. However, there is some good news from this study;
namely, the indication that the majority of those infected with coronavirus did
not shed virus in either droplets or aerosols!
Summary Considerations
In summary, I have reviewed two primary literature sources and one secondary source. All of them provide significant findings that should be taken into consideration when policy makers and we as individuals decide on whether or not to wear a mask; and, for what purpose, or what kind of mask, or how to avoid increasing risk of infection as a mask-wearer. Perhaps most telling to us is whether we have been surprised by any of the results reported in these three studies. I suggest that the degree to which we are surprised reflects the degree to which we have depended solely on broadcast media (secondary sources) as most Americans do.
Unless we have a media source that does the hard work of extracting results from primary scientific sources, and reports it objectively without political bias, we will not be able to do as many say we should do-- “just follow the science.” In the case of mask wearing, as I have discussed here, there appears to be “good science” and at least some good journalism, suggesting that we do well not to put too much trust in cotton cloth masks even if there are dozens of websites that tell us how to make cloth masks. Furthermore, depending how we use the mask we could even increase our risk of infection. Nor is there clear evidence that masks are stopping aerosol transmission of virus as much as the fact that virus shedding by infected individuals may be much less than we imagine.
Nature Medicine Study
This report, published online April 3, 2020, is a primary source from a reputable journal. The study was conducted from March, 2013 through May, 2016 in a general outpatient clinic of a private hospital in Hong Kong. Researchers “screened 3,363 individuals in two study phases, ultimately enrolling 246 individuals who provided exhaled breath samples. Among these 246 participants, 122 (50%) participants were randomized to not wearing a face mask during the first exhaled breath collection and 124 (50%) participants were randomized to wearing a face mask. Overall, 49 (20%) voluntarily provided a second exhaled breath collection of the alternate type.”
Virus Transmission in Air: “Our results indicate that aerosol transmission is a potential mode of transmission for coronaviruses as well as influenza viruses and rhinoviruses.”
Efficacy of Masks: “Our findings indicate that surgical masks can efficaciously reduce the emission of influenza virus particles into the environment in respiratory droplets, but not in aerosols.”
Very Little Virus Shedding: “Among the samples collected without a face mask, we found that the majority of participants with influenza virus and coronavirus infection did not shed detectable virus in respiratory droplets or aerosols…”
Summary Considerations
In summary, I have reviewed two primary literature sources and one secondary source. All of them provide significant findings that should be taken into consideration when policy makers and we as individuals decide on whether or not to wear a mask; and, for what purpose, or what kind of mask, or how to avoid increasing risk of infection as a mask-wearer. Perhaps most telling to us is whether we have been surprised by any of the results reported in these three studies. I suggest that the degree to which we are surprised reflects the degree to which we have depended solely on broadcast media (secondary sources) as most Americans do.
Unless we have a media source that does the hard work of extracting results from primary scientific sources, and reports it objectively without political bias, we will not be able to do as many say we should do-- “just follow the science.” In the case of mask wearing, as I have discussed here, there appears to be “good science” and at least some good journalism, suggesting that we do well not to put too much trust in cotton cloth masks even if there are dozens of websites that tell us how to make cloth masks. Furthermore, depending how we use the mask we could even increase our risk of infection. Nor is there clear evidence that masks are stopping aerosol transmission of virus as much as the fact that virus shedding by infected individuals may be much less than we imagine.
What Do You Think About It?
As always, I welcome your opinions, corrections, questions. Just use the “Comments” link below. And, if you would like another COVID-19 related
topic to research “back into the science,” consider hydroxychloroquine which as
been shown to be efficacious against COVID-19 if prescribed appropriately but
which has been opposed vehemently by many in the liberal media. See Hydroxychloroquine: “Good Science”
Challenges Politicized Science and a
recent interview with Dr. Harvey Risch, Yale
epidemiologist. Why aren’t we following
the science?”
Good and timely article, John. Another issue with masks that maybe should be considered is the probability that they can weaken our immune systems rather than strengthening them since we aren't allowing them to get their normal and intended workouts of dealing with germs, bacteria, and viruses. The result is likely making us more vulnerable, not less, to illnesses we would normally be able to fight off with immune systems operating at peak efficiency. It's hard to understand why our government and the media have not encouraged more the building up of our immune systems and how best to do it. This would be wise since there will presumably come a day soon when those who wear masks will no longer be wearing them. As well, considering your article's sources, building immune systems is even more important WHILE you wear the mask to help fight the germs, bacteria, and viruses we are rebreathing and/or creating (from moisture buildup and such) on the masks.
ReplyDeleteExcellent points, Ken. There is no doubt that wearing a mask changes the entire environment of our respiratory intake including our interaction with airborne microbes, both by alterations in humidity and other gaseous relationships and by likely concentration of microbes on the moist surfaces and within the fibrous matrix of the mask.
ReplyDeleteI also agree that practices that attempt to protect us AND shelter our immune system AND so many other aspects of our lives from the rigors (and the benefits) of interfacing directly with the atmosphere, soil, and water are making us less and less independent and less able to face the never-ending challenges to human life. Thanks for seeking to keep informed and remaining vigilant.
Thanks, John, for keeping us laymen up on the original source material. I'm reminded of what Cornelius Van Til (via Greg Bahnsen) said regarding "evidence".
ReplyDelete"All empirical observation is inescapably theory-laden (there are no uninterpreted 'brute facts'). The acceptance and interpretation of what one takes as 'factual' is not determined by sense perception alone, but in interaction with one's fundamental philosophical convictions (there is no presuppositionless neutrality)."