Wishful Science
Literature Review Number 3: COVID-19 Series
Is there any valid reason for Community Face Masks?
The COVID-19 debacle has been brought to its current fevered pitch by the rejection of science by government officials and the abdication of sound scientific reasoning by many of their advisors. Many (usually Left of center) government officials are citing "science" that simply doesn't exist, and many of their advisors are citing "studies" that do not present what the advisor thinks the study says, or perhaps what the advisor wished the study says.
This is my third review of literature that is being cited by some people who support community wide mask-wearing and who believe that science is on their side and they believe that this study supports Community Mask Wearing.
Article Under Review
Anna Davies, BSc, Katy-Anne Thompson, BSc, Karthika Giri, BSc, George Kafatos, MSc, Jimmy Walker, PhD, and Allan Bennett, MSc
Testing the Efficacy of Homemade Masks: Would They Protect in an Influenza Pandemic? (Disaster Med Public Health Preparedness. 2013;7:413-418)
Earlier this year, I had already discussed this particular research paper. In the earlier discussion, I discussed how the research findings were being misrepresented on social media and I was addressing the misinformation on social media rather than the article itself. That discussion can be found here: "Size Matters."
But, more recently, someone has asked me to share my thoughts on the article itself.
As discussed in the article, the research team evaluated homemade masks to evaluate the efficacy of such masks in the event of an influenza outbreak. To perform the investigation, the research team used two surrogate entities Bacillus atrophaeus (a rod-shaped spore-forming bacterium of 0.95-1.25 μm aerodynamic diameter) and the virus called "Bacteriophage MS2" (MCIMB10108) which is a nonenveloped single-stranded RNA coliphage, (0.023 - 0.28 μm in diameter). The two test organisms can be compared in size to the influenza virus, which ranges from 0.06 to 0.10 μm, and smaller droplet nuclei.
For much the same reason the researchers could use their surrogates as a substitute for the influenza virus in their study, today we can use the observations they made and apply those lessons to the SARS-CoV-2 virus (which is a +sense strand RNA virus 0.06 to 0.14 μm). Crossover information like this is very common and appropriate, as has been explicitly noted elsewhere.[i]
In general, the authors of this paper did a stellar job of making the research meaningful and practical. The methodology for the study was meant to be translatable into information germane to the "man on the street."
Essentially, the research consisted of two distinct parameters 1) the intrinsic filtering efficiencies of various materials, and 2) the practical efficacy of an homemade mask to prevent the spread of droplets by the wearer.
Notice that language carefully because the authors did not study the ability of the masks to prevent the spread of infection - and that is a very different discussion to be had.
If one sees this paper in a reference, be careful about how it may be cited since the authors make statements that, on the surface, appear to be conflicting and even contradictory, if taken out of context.
For example, the opening sentence of the introduction states:
Wearing a face mask in public areas may impede the spread of an infectious disease by preventing both the inhalation of infectious droplets and their subsequent exhalation and dissemination.
That statement is followed up with:
However, the evidence of proportionate benefit from widespread use of face masks is unclear.
Ultimately, the authors make the assertion that although a homemade face mask may reduce the risk of infection, the reduction is not likely to be of any great benefit and:
As a result, we would not recommend the use of homemade face masks as a method of reducing transmission of infection from aerosols.
This ultimate conclusion is based primarily on the recognition that a mask may reduce the likelihood of infection, but it will not eliminate the risk, particularly when a disease has more than one route of transmission. That is to say, a simplistic approach to protection will result in people having an overestimation of the efficacy of the mask since the protection factors observed by these authors were only on the order of 2 (that is a reduction of contaminant by a factor of 2).
So imagine that in the case of the SARS-CoV-2 virus, the viral burden is similar to the average concentration of Streptococcus organisms in saliva referenced by the authors of this study (6.7 E7 CFU/ml of saliva). And imagine that an infected person is wearing a mask during coughing, or speaking with "moist pronunciations." Producing a tenth of a ml of saliva, that person may generate a cloud of some 6,000,000 infectious particles that is introduced to the mask. With a reduction factor of 2, there are now 3,000,000 infectious particles that have left the wear's mask and are now available to another (also masked) person in the area.
With that person's mask reduction factor of 2, that masked person now is exposed to 1,500,000 infectious particles. But what if the infectious dose for SARS-CoV-2 is only 100 particles? This means that the mask is so grossly inadequate, that from a practical perspective, one has no mask on at all. From a strictly statistical perspective, there is no difference between the exposures from the same two persons whether wearing the masks or not wearing any masks at all.
Wearing a mask is rather like a firefighter taking only a toy water-pistol with him as he sets out to fight a blazing fire in a five-story structure. Is the toy water-pistol "better than nothing?" Of course, but it is still useless, and there is no difference in the result of fighting the fire while having the water-pistol and not having the water-pistol; the fire fighter will not save the building. (In fact, it is a little worse than that, because in this analogy, the firefighter's water-pistol is filled with gasoline, reflecting the fact that the person wearing the mask has actually increased their probability to exposure to pathogens).
It's for this reason the authors state:
Thus any mask, no matter how efficient at filtration or how good the seal, will have minimal effect if it is not used in conjunction with other preventative measures, such as isolation of infected cases, immunization, good respiratory etiquette, and regular hand hygiene.
An improvised face mask should be viewed as the last possible alternative if a supply of commercial face masks is not available, irrespective of the disease against which it may be required for protection.
Similarly, the authors mention (but don't go into any great detail), the recognized fact that the wearing of homemade masks by untrained people is likely to result in an increased risk of illness that would otherwise eliminate any remaining reduction in risk and for all those reasons, the authors' ultimate conclusion is
As a result, we would not recommend the use of homemade face masks as a method of reducing transmission of infection from aerosols.
To date - there is no scientifically sound rationale in support of the current craze of "face-masks." Certainly, there is no support for the fad to be found in this study. The best data available indicates the face masks are at best useless, and at worse, probably increasing the risk of the wearer being exposed to both SARS-CoV-2 and other pathogens.
Caoimhín P Connell
Forensic Industrial Hygienist
May 27, 2020
Previous reviews -
Other COVID-19 discussions by CP Connell:
How to Peddle Backward - What happened to the 2020 Flu Epidemic? A summary of the US Crude Mortality Rate's refusal to cooperate with the popular narrative.
WHO thought this was a good idea... (Comments regarding the December 1, 2020, "Mask use in the context of COVID-19".)
The Failing Mask Cure Aid a review of Bundgaard H, Bundgaard JS, Raaschou-Pedersen DET, et al, "Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers, A Randomized Controlled Trial" (Ann. Int. Med. Nov 18, 2020, https://doi dot org/10.7326/M20-6817).
Don't be a Maskhole, Karen A review of Zeng N, Li Z, Ng S, Chen D, Zhou H, Epidemiology reveals mask wearing by the public is crucial for COVID-19 control. (Medicine in Microecology, https://doi.org/10.1016/j.medmic.2020.100015):
Masks, and the new Doctor Schnabel von Rom: Review of Stadnytskyi V, Bax CE, Bax A, Anfinru P, The airborne lifetime of small speech droplets and their potential importance in SARS-CoV-2 transmission (Approved by PNAS May 2020: https://www.pnas.org/cgi/doi/10.1073/pnas.2006874117)
Pathological Science - Zhang et al and the PNAS: Zhang R, Annie Y Zhang L, Wang Y, Molinae M: Identifying airborne transmission as the dominant route for the spread of COVID-19 (fast-tracked through the PNAS on June 11, 2020)
Defacing Mask Science - Rossettie S, Perry C, Pourghaed M, Zumwalt M, "Effectiveness of manufactured surgical masks, respirators, and home-made masks in prevention of respiratory infection due to airborne microorganisms" The Southwest Respiratory and Critical Care Chronicles 2020;8(34):11–26
Masks - Don't look behind the curtain: Review of Vivek Kumar, Sravankumar Nallamothu, Sourabh Shrivastava, Harshrajsinh Jadeja, Pravin Nakod, Prem Andrade, Pankaj Doshi, Guruswamy Kumaraswamy "On the utility of cloth facemasks for controlling ejecta during respiratory events "
Size matters! A Brief Description of filtering mechanisms and size.
Materials v. Masks: A review of Konda A, Prakash A, Moss GA, Schmoldt M, Grant GD, Guha S "Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks" (American Chemical Society, April 2020)
"Junk Science: In Favor of Community Face Masks - a return to Lysenkoism" A review of: Jeremy Howard, Austin Huang, Zhiyuan Li, Zeynep Tufekci, Vladimir Zdimal, Helene-Mari van der Westhuizen, Arne von Delft, Amy Price, Lex Fridman, Lei-Han Tang, Viola Tang, Gregory L. Watson, Christina E. Bax, Reshama Shaikh, Frederik Questier, Danny Hernandez, Larry F. Chu, Christina M. Ramirez, Anne W. Rimoin Face Masks Against COVID-19: An Evidence Review NOT PEER-REVIEWED | Posted: 13 May 2020
If Manikins Could Fly… A Review of Eikenberry SE, Mancuso M, Iboi E, Phan T, Eikenberry K, Kuang Y, Kostelich E, Gumel AB "To mask or not to mask: Modeling the potential for face mask use by the general public to curtail the COVID-19 pandemic" (Infectious Disease Modelling 5 (2020) pp. 293-308)
Review of Cheng VC, Wong S, Chuang V, So S, et al "The role of community-wide wearing of face mask for control of coronavirus disease 2019 (COVID-19) epidemic due to SARS-CoV-2" (Journal of Infection April 30, 2020;16:13)
Gassed Masks! Reactivation of viruses and deoxygenation during mask wearing.
Masking the Truth - A discussion of aerosols and droplets
We R0 New York City - A discussion of the basic reproduction number.
The epidemic of ignorance: Lessons from "Flattening the Curve" April 14, 2020
Think Tanks! The Dangers of Group-Think April 13, 2020
References:
[i] Morawska L, Tang JW, Bahnfleth W, Bluyssen PM, "How can airborne transmission of COVID-19 indoors be minimised?" Environment International (Elsevier) Available online 27 May 2020, https://doi.org/10.1016/j.envint.2020.105832