Mask Myths and YES Masks Are Effective

In today’s Medium article I’ll be discussing the myths commonly shared by people who look at too much AV propaganda trope online without doing background referencing on the claims made, and looking at studies of masks, with a long list of studies (including meta-analysis) which will put the strawman to bed once and fall.

Spoiler: masks work and are highly effective at preventing transmission.

➡ Mask Myths
Time and time again we see so many false claims about masks. Below are some of the false claims being made.

💥 Masks do not hinder oxygen levels
As demonstrated by this doctor undertook a run to demonstrate this. (Source:

Masks don’t interfere with lung function or oxygen intake in any meaningful way for healthy people. (Source:

Furthermore, there are documented cases of people habitually wearing masks for high-intensity exercise without any apparent ill effects — for instance, athletes who train in elevation masks, which are specifically designed to stress the respiratory system, are still safe to use. (Source:

It’s likely to be much more uncomfortable than a cloth mask, and that feeling of discomfort could affect your performance. (Source:

Masks cannot kill. (Source:

Masks do not lower your oxygen intake or have high C02 levels. (Source:

They don’t cause health problems. (Source:

➡ Are masks healthy?
VUMC seems to think so. (Source:

➡ Peer-reviewed Study Evidence

💥 Mask RCT studies
Hand hygiene and facemasks seemed to prevent household transmission of influenza virus when implemented within 36 hours of index patient symptom onset. These findings suggest that nonpharmaceutical interventions are important for mitigation of pandemic and interpandemic influenza.” (Source:

(First Randomized, Controlled Clinical Trial of Mask Use in Households)
“In an adjusted analysis of compliant subjects, masks as a group had protective efficacy above 80% against clinical influenza-like illness” (Source:

The role of facemasks and hand hygiene in the prevention of influenza transmission in households: results from a cluster randomised trial; Berlin, Germany, 2009–2011. (Source:

Surgical masks reduce COVID transmission. A large randomised control trial that has 350,000 people has shown a 35% risk reduction for community interventions (Source:

💥 Meta-analysis studies
D.K. Chu, S. Duda, K. Solo, S. Yaacoub, H. Schunemann
“Physical Distancing, Face Masks, and Eye Protection to Prevent Person-to-Person Transmission of SARS-CoV-2 and COVID-19: A Systematic Review and Meta-Analysis”

Yanni Li MPH, Mingming Liang MPH , Liang Gao MD PhD, Ce Cheng DO, Qin Zhou PhD, Chenyu Sun MD MSc
“The results of this systematic review and meta-analysis support the conclusion that wearing a mask could reduce the risk of COVID-19 infection.” (Source:

“Masks protect HCWs and other populations against respiratory viral infection.” (Source:

Efficacy of face mask in preventing respiratory virus transmission: A systematic review and meta-analysis. (Source:

➡ An evidence review that supports mask-wearing with over 110 references
Our review of the literature offers evidence in favour of widespread mask use as source control to reduce community transmission: Nonmedical masks use materials that obstruct particles of the necessary size; people are most infectious in the initial period postinfection, where it is common to have few or no symptoms; nonmedical masks have been effective in reducing transmission of respiratory viruses, and places and periods mask usage is required or widespread have shown substantially lower community transmission.

The available evidence suggests that near-universal adoption of nonmedical masks when out in public, in combination with complementary public health measures, could successfully reduce ReRe to below 1, thereby reducing community spread if such measures are sustained. Economic analysis suggests that mask-wearing mandates could add 1 trillion dollars to the US GDP. (Source:

➡ Other relevant study evidence
Association of country-wide coronavirus mortality with demographics, testing, lockdowns, and public wearing of masks:

Cloth face coverings, even homemade masks made of the correct material, are effective in reducing the spread of COVID-19 — for the wearer and those around them:

“Societal norms and government policies supporting the wearing of masks
by the public, as well as international travel controls, are independently associated with
lower per-capita mortality from COVID-19.”

The introduction of a mandatory mask policy was associated with an estimated 23% reduction in the effective reproduction ratio, from 1.18 to 0.91. The mandatory mask use policy substantially increased public use of masks and was associated with a significant decline in COVID-19 transmission after the introduction of the policy:

“Face mask use could result in a large reduction in risk of infection (n=2647; aOR 0·15, 95% CI 0·07 to 0·34, RD -14·3%, -15·9 to -10·7; low certainty), with stronger associations with N95 or similar respirators compared with disposable surgical masks or similar (eg, reusable 12–16-layer cotton masks; pinteraction=0·090; posterior probability >95%, low certainty).”:

Exposing society to SARS-CoV-2 without the unacceptable consequences of severe illness with public masking could lead to greater community-level immunity and slower spread as we await a vaccine.

“Our results indicate that, in times of shortage, N95 respirators can be decontaminated and reused up to 3 times by using UV light and HPV and 1–2 times by using dry heat.”

Very good read:

“In conclusion, our findings suggest that face mask use should be as nearly universal (i.e., nationwide) as possible and implemented without delay, even if most masks are homemade and of relatively low quality.”

“Mask wearing by all individuals, supported by proper education and training of mask making and appropriate usage, can be an effective strategy in conjunction with social distancing, testing and contact tracing, and other interventions to reduce disease transmission.”

We show that during indoor coughing some saliva particulates could travel up to 0.48 m, 0.73 m, and 2.62 m for the cases with medical-grade, non-medical grade, and without facial masks, respectively. Thus, in indoor environments either medical or non-medical grade facial masks can successfully limit the spreading of saliva particulates to others:

Based on the literature reviewed, it is safe to say that wearing face masks at the community level and in medical settings will decrease the spread of COVID-19 by 1. Preventing Sars-CoV-2 droplets from leaving the infected wearer and entering the environment. 2. Preventing Sars-CoV-2 droplets from entering the respiratory tract of the uninfected wearer:

However, the use of MNC seems to be linked to relevant protection during close contact scenarios by limiting pathogen-containing aerosol and liquid droplet dissemination. (for context MNC = mouth and nose covering):

Multilayer cloth masks, designed to fit around the face and made of water-resistant fabric with a high number of threads and finer weave, may provide reasonable protection:

Community-wide mask-wearing may contribute to the control of COVID-19 by reducing the amount of emission of infected saliva and respiratory droplets from individuals with subclinical or mild COVID-19:

Our findings provided valuable details of pre-symptomatic patient mask-wearing and restriction of mass gathering in congested spaces particularly, are important interventions to mitigate the SARS-CoV-2 transmission:

Viral particles were not found in the Petri dishes after coughing while wearing the N95 mask or the KF94 mask:

We produced the mask and carried out subjective testing on a user in a typical workplace setting; we demonstrated that the mask was form-fitting, customizable, washable, and could be worn continuously and routinely over extended periods of time by individuals and therefore could serve as an effective means to reduce the harm from SARS-CoV-2:

The potential of face masks to reduce the spread of respiratory infections could be useful. Wang et al1 indicated that 10 of 213 medical professionals with no mask were infected by COVID-19 as compared with 0 of 278 wearing N95 respirators:

One recent study in BMJ Global Health looked at transmission of SARS-CoV-2 in 124 families in which at least one member had COVID-19. The data showed that face masks were “79% effective in reducing transmission” if the person with COVID-19 wore them before they developed symptoms.

Prof. Trisha Greenhalgh from the University of Oxford in the United Kingdom has voiced her support about using face masks in several prominent research journals, such as The BMJ.

Research papers have shown that simple face coverings can reduce the number of droplets, and perhaps some aerosols, to some extent.

An experiment using high-speed video found that hundreds of droplets ranging from 20 to 500 micrometres were generated when saying a simple phrase, but that nearly all these droplets were blocked when the mouth was covered by a damp washcloth.

The latest forecast from the Institute of Health Metrics and Evaluation suggests that 33,000 deaths could be avoided by October 1 if 95 percent of people wore masks in public.

“In our investigation, the transmission may have been mitigated by mild symptoms and masking during the flight”

➡ Conclusion
Masks work, prevent the transmission of Covid-19, there is nothing else to add, the evidence is too overwhelming to say otherwise.

💥 Thanks for reading, Lawrence. Please consider a small contribution, in the form of a beer as all articles are created in my small amount of spare time:




Passionate about evidence-based scientific information and tackling falsehoods that thrive on social media.

Love podcasts or audiobooks? Learn on the go with our new app.

Recommended from Medium

Man’s death in NW Ohio reopens Canadian cold case


Low Risk of Blood Clots and Low Platelet Count for Covid-19 Vaccination-Evidence Based

Debunking an “Origin of COVID” Conspiracy Theory

The COVID Eye of the Tiger

My College Has 2 Confirmed Cases

New Data: Vitamin D Supplements Unlikely to Prevent COVID-19

Top 10 Videos of 2021

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Lawrence Robinson

Lawrence Robinson

Passionate about evidence-based scientific information and tackling falsehoods that thrive on social media.

More from Medium

Don’t Look Up: A final call for action


Hindsight is 20/20 but here’s to hoping 2022 is better.

I am Sarah. I am just Sarah.