Mask wearing and Covid-19

There has been very mixed information, study results, and opinions on whether or not wearing face coverings does or does not help reduce the transmission of a virus such as SARS-CoV-2. At this time (January 2022) the science remains unclear.

On a personal level — In March 2020 one of our authors read through a large number of pre-Covid-19 studies and science journal papers, spanning the past few decades, on the practice of wearing masks, in relation to preventing or reducing virus transmission. The purpose of his investigation at that time was for personal reasons, to ascertain if he should obtain some form of face mask for self-protection from what at that time was a relatively unknown virus. He determined there was no evidence indicating a significant benefit to the person wearing a regular face mask (dust masks, N95 masks, and surgical masks). To receive any benefit to the wearer it was apparent a full face mask (covering the eyes, nose, and mouth) with certified biological filters or a forced filtered air feed would be necessary.

Within the mainstream narrative on wearing of face coverings, the rationale eventually changed to the idea that wearing the mask is for protecting other people, as opposed to protecting the mask wearer. The idea being that if the wearer is infected and contagious, the face covering may help reduce the aerosol spread and distribution of virus particles. Yet whether or not this is “true” or of any meaningful consequence depends on which study you consider, and who you ask. Study results have been mixed.

Studies in support of mask wearing to curtail Covid-19

1. ASM Journal — Effectiveness of Face Masks in Preventing Airborne Transmission of SARS-CoV-2 — 21 October 2020
   CONCLUSION: “Airborne simulation experiments showed that cotton masks, surgical masks, and N95 masks provide some protection from the transmission of infective SARS-CoV-2 droplets/aerosols; however, medical masks (surgical masks and even N95 masks) could not completely block the transmission of virus droplets/aerosols even when sealed.”

Studies NOT in support of mask wearing to curtail Covid-19

1. JEHP — Efficacy of cloth face mask in prevention of novel coronavirus infection transmission: A systematic review and meta-analysis — 28 July 2020
   CONCLUSION: “Cloth face masks have limited efficacy in combating viral infection transmission. However, it may be used in closed, crowded indoor, and outdoor public spaces involving physical proximity to prevent spread of SARS-CoV-2 infection.”
2. ACP Journal — Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers — March 2021
   CONCLUSION: “The recommendation to wear surgical masks to supplement other public health measures did not reduce the SARS-CoV-2 infection rate among wearers by more than 50% in a community with modest infection rates, some degree of social distancing, and uncommon general mask use. The data were compatible with lesser degrees of self-protection.”
3. IEE — Face masks vs. COVID-19: a systematic review — 10 July 2020
   CONCLUSION: “There is little evidence to support the effectiveness of face masks to reduce the risk of COVID-19 infection. However, the use of N95 respirators or air supplying respirators and adherence to the principles of personal hygiene, frequent hand washing and the use of disinfectants can reduce the prevalence of COVID-19 in health care providers. Due to the novelty of the COVID-19 virus, no clinical trials have been found on the use of face masks in disease prevention. Also, the use of face masks by people in the community, in addition to other health principles can help in reducing the prevalence of COVID-19 disease.”

Articles suggesting benefits to mask wearing

1. Stanford Medicine News — Surgical masks reduce COVID-19 spread, large-scale study shows — 1 September 2021
   “A large, randomized trial led by researchers at Stanford Medicine and Yale University has found that wearing a surgical face mask over the mouth and nose is an effective way to reduce the occurrence of COVID-19 in community settings.”
2. University of California San Francisco — Still Confused About Masks? Here’s the Science Behind How Face Masks Prevent Coronavirus — 26 June 2020
3. PNAS — An evidence review of face masks against COVID-19 — 10 April 2020
4. EPA — EPA Researchers Test Effectiveness of Face Masks, Disinfection Methods Against COVID-19 — 5 April 2021

Articles suggesting nominal or no benefit to mask wearing

1. MSN (Microsoft News) — Do masks actually work? The best studies suggest they don’t — 12 August 2021
   “In sum, of the 14 RCTs that have tested the effectiveness of masks in preventing the transmission of respiratory viruses, three suggest, but do not provide any statistically significant evidence in intention-to-treat analysis, that masks might be useful. The other eleven suggest that masks are either useless — whether compared with no masks or because they appear not to add to good hand hygiene alone — or actually counterproductive. Of the three studies that provided statistically significant evidence in intention-to-treat analysis that was not contradicted within the same study, one found that the combination of surgical masks and hand hygiene was less effective than hand hygiene alone, one found that the combination of surgical masks and hand hygiene was less effective than nothing, and one found that cloth masks were less effective than surgical masks.”
2. River Cities Reader — Masks Don’t Work: A Review of Science Relevant to COVID-19 Social Policy — 11 June 2020
   “There have been extensive randomized controlled trial (RCT) studies, and meta-analysis reviews of RCT studies, which all show that masks and respirators do not work to prevent respiratory influenza-like illnesses, or respiratory illnesses believed to be transmitted by droplets and aerosol particles.”
3. River Cities Reader — Still No Conclusive Evidence Justifying Mandatory Masks — 12 August 2020
4. Fee Stories — New Danish Study Finds Masks Don’t Protect Wearers From COVID Infection — 18 November 2020
   See the actual study paper in the Studies section above
5. Townhall — Masks Didn’t Slow COVID Spread: New Study — 26 May 2021
   “New findings reported Tuesday in a University of Louisville study challenge what has been the prevailing belief that mask mandates are necessary to slow the spread of the Wuhan coronavirus. The study notes that “80% of US states mandated masks during the COVID-19 pandemic” and while “mandates induced greater mask compliance, [they] did not predict lower growth rates when community spread was low (minima) or high (maxima).” Among other things, the study—conducted using data from the CDC covering multiple seasons—reports that “mask mandates and use are not associated with lower SARS-CoV-2 spread among US states.”

Negative Side-effects of Wearing Face Masks

It would be remiss to only consider whether or not face coverings / masks reduce transmission of SARS-CoV-2, without also looking at whether there are any detrimental side-effects of such practices.

1. MEHY — COVID-19: Electrophysiological mechanisms underlying sudden cardiac death during exercise with facemasks — 11 August 2020
   CONCLUSION: “In conclusion, exercise with facemasks may increase the risk of SCD via the development of acute and/or intermittent hypoxia and hypercapnia. The hypothesized mechanisms include increased adrenergic stimulation, increased oxidative stress leading to electrophysiological abnormalities that promote arrhythmias via non-reentrant and reentrant mechanisms. Given the interplay of multiple variables contributing to the increased arrhythmic risk, we advise avoidance of a facemask during high intensity exercise, or if wearing of a mask is mandatory, exercise intensity should remain low to avoid precipitation of lethal arrhythmias. However, we cannot exclude the possibility of an arrhythmic substrate even with low intensity exercise especially in those with established chronic cardiovascular disease in whom baseline electrophysiological abnormalities may be found.

Excessive CO2 inhalation?

In the United Kingdom the Workplace Exposure Limit for CO2 is as follows:

• Long-term exposure limit (8-hr reference period) of 5000 ppm
• Short-term exposure limit (15 minute reference period) of 15000 ppm

In Canada OSH sets similar limits, specifically:

• ACGIH® TLV® – TWA: 5000 ppm
• ACGIH® TLV® – STEL [C]: 30000 ppm
• Exposure Guideline Comments: TLV® = Threshold Limit Value. TWA = Time-Weighted Average. STEL = Short-term Exposure Limit. C = Ceiling limit.

Wisconsin Department of Health Services published the following guidelines (Last Revised: June 3, 2021):

We’ve found videos from numerous people doing their own CO2 measurements using relevant equipment. In all cases, these people found that CO2 levels within the mask were excessive to extreme levels. All such videos were banned (censored) from the mainstream social media platforms. “Fact checker” web sites were abound with articles discrediting all such tests and videos.

On May 11th 2022 a pre-print study was released on medrxiv.org titled, “Inhaled CO2 concentration while wearing face masks: a pilot study using capnography“. The results of this study show similar high CO2 concentration as many of the lay-person tests previously discredited. It hasn’t yet been pair reviewed, so it remains to be seen whether the study is accepted as valid and useful. A summary of the study findings are:

The mean CO₂ concentration was 4965±1047 ppm with surgical masks, and 9396±2254 ppm with FFP2 respirators. The proportion of the sample showing a CO₂ concentration higher than the 5000 ppm acceptable exposure threshold recommended for workers was 40.2% while wearing surgical masks, 99.0% while wearing FFP2 respirators. The mean blood oxygen saturation remained >96%, and the mean end-tidal CO₂ <33 mmHg. Adjusting for age, gender, BMI, and smoking, the inhaled air CO₂ concentration significantly increased with increasing respiratory rate (with a mean of 10,143±2782 ppm among the participants taking 18 or more breaths per minute, while wearing FFP2 respirators), and was higher among the minors, who showed a mean CO₂ concentration of 12,847±2898 ppm, while wearing FFP2 respirators.

SOURCE: https://www.medrxiv.org/content/10.1101/2022.05.10.22274813v1

There was an earlier study published on July 15, 2020, titled, “Effect of Wearing Face Masks on the Carbon Dioxide Concentration in the Breathing Zone“. The study author is Otmar Geiss, and was backed by European Commission, Joint Research Centre (JRC), Ispra, Italy. On that particular publishing platform we don’t see any way to determine if the study has been peer reviewed or not. The study looks like it was conducted in a fairly similar fashion to many of those done by lay-people and published online (and subsequently censored). The study authors conclude that:

Measurements were made using a modified indoor air quality meter equipped with a nondispersive infrared (NDIR) CO₂ sensor. Detected carbon dioxide concentrations ranged from 2150 ± 192 to 2875 ± 323 ppm. The concentrations of carbon dioxide while not wearing a face mask varied from 500–900 ppm. Doing office work and standing still on the treadmill each resulted in carbon dioxide concentrations of around 2200 ppm. A small increase could be observed when walking at a speed of 3 km h^–1 (leisurely walking pace). Walking at a speed of 5 km h^–1, which corresponds to medium activity with breathing through the mouth, resulted in an average carbon dioxide concentration of 2875 ppm. No differences were observed among the three types of face masks tested. According to the literature, these concentrations have no toxicological effect. However, concentrations in the detected range can cause undesirable symptoms, such as fatigue, headache, and loss of concentration.

SOURCE: https://aaqr.org/articles/aaqr-20-07-covid-0403

In October 2021, the quality of the above-mentioned Geiss study was brought into question by another (pre-print) study titled, “Effect of Wearing FFP2 Face Masks on the CO2 Concentration in the Breathing Zone“. It was published by by Lorenzo Zago, a Professor from University of Applied Sciences and Arts Western Switzerland · IAI – Institut d’Automatisation Industrielle.

He made the following observations about the Geiss study:

… it can be immediately remarked that the experimental setup was faulted. The concentration of carbon dioxide in the breathing zone was determined by aspirating air through a vertical silicon tube from the breathing zone behind the face mask. The sampling point was just above the nose tip on the bridge of the nose. It is then quite apparent that the aspiration rate, operated by a pump but not reported in the paper, will affect the measured concentration of CO2.

On the one hand, aspiring through the mask more air than the quantity normally inspired by the subject, will unavoidably dilute the inhaled CO2. But also if the aspiration rate is set low, the CO2 being heavier than air, its concentration after a vertical tube directed against gravity will not be verifiably representative of what is actually inhaled by the nose. Such fundamental faults in the test setup make the ref. [1] study conclusions very unreliable.

SOURCE: https://www.researchgate.net/publication/355362268_Effect_of_Wearing_FFP2_Face_Masks_on_the_CO2_Concentration_in_the_Breathing_Zone

Professor Lorenzo Zago states the following as his rationale for conducting the study:

On December 20, 2021, Dr. PAUL ELIAS ALEXANDER published an article, sharing the results of his analysis of 167 studies on “More than 150 Comparative Studies and Articles on Mask Ineffectiveness and Harms“. His conclusion is that, “To date, the evidence has been stable and clear that masks do not work to control the virus and they can be harmful and especially to children.” It’s well worth looking at the various studies cited in that article.

A workplace safety company in Australia published their views on mask wearing, concluding that there’s no harm from mask wearing. The only study they cite in their article is the Geiss study mentioned above, which is referred to as, “authoritative research”. In our opinion it’s a stretch to refer to the one stand-alone study as authoritative research.

Fiber and Chemicals in the lungs?

30 December 2020 — COVID-19: Performance study of microplastic inhalation risk posed by wearing masks

NOTES — Other related info

US Military Health System — Mask Mouth Does Not Exist, Dentists Say — 6 October 2021