The question of whether we should wear face masks or not to prevent the spread of COVID-19 is a hotly contested issue. Part of the confusion may be related to the difference between viral particles spread via respiratory droplets, and viral particles spread via the air itself.
I believe it’s important to realize the difference between these two modes of transmission, and to not overestimate the protection you can get or give others by wearing a mask.
The science1,2 clearly shows face coverings of various kinds do little if anything to prevent respiratory illnesses caused by aerosolized viruses. Many health authorities still insist that something is better than nothing, though, since they do inhibit the dissemination of viral-laden respiratory droplets.
But influenza viruses — coronaviruses that cause the common cold and SARS-CoV-2 — all spread via the air, not just via droplets or touching contaminated surfaces, and it’s important to realize that preventing droplet contamination does not mean you also prevent the transmission of the aerosolized virus. (The aerosol part of transmission is regrettably overlooked in the video above, which reviews a number of problems with mandatory mask recommendations.)
SARS-CoV-2 is an aerosolized virus, meaning it floats in the air. One of the issues at hand is the size of the virus. If the gaps in the mask are larger than the virus, it stands to reason it cannot block the virus from entering or escaping the mask.
SARS-CoV-2 is a beta-coronavirus with a diameter between 60 nanometers (nm) and 140 nm, or 0.06 to 0.14 microns (micrometers).3 This is about half the size of most viruses, which tend to measure between 0.02 microns to 0.3 microns.4
Virus-laden saliva or respiratory droplets expelled when talking or coughing, however, measure between 5 and 10 microns.5 N95 masks can filter particles as small as 0.3 microns,6 so they may prevent a majority of respiratory droplets from escaping, but not aerosolized viruses.
Lab testing7 has shown 3M surgical masks can block up to 75% of particles measuring between 0.02 microns and 1 micron, while cloth masks block between 30% and 60% of respiratory particles of this size. For cloth masks, cotton-chiffon, cotton-silk hybrids, and high thread count cotton materials provide the best droplet filtration. As reported by the Emergency Medicine News journal:8
“Mueller, et al.,9 placed a particle counter inside various masks worn by a volunteer to sense 0.04 micron NaCl particles aerosolized in ambient air, and found that adding a nylon stocking overlayer to the mask improved virus blockade for all types, including surgical masks. This simple addition improved many of the homemade cloth masks to the baseline level of a surgical mask.”
So, in summary, if you are a carrier of the virus, by wearing a surgical mask, you theoretically lower the amount of viral-laden respiratory droplets that you deposit into your environment by about 75%.
As such, you could argue that surgical masks lower the overall contamination risk to others if you are a carrier of the virus. If you are infected and wear a surgical mask, others in close proximity will be protected to some degree from getting hit by your contaminated respiratory droplets.
That said, the force by which you expel the droplets also matters. Back in April 2020, a small South Korean study10 found that surgical and cloth masks were unable to block SARS-CoV-2 from the coughs of COVID-19 patients. The journal retracted the paper several weeks later.11,12
Masks Cannot Block Aerosolized Viruses
The virus is not restricted to respiratory droplets, though. It’s also in the air itself, and these aerosolized particles are far tinier. To block these, you’d need a mask that prevents all air flow, and that, of course, wouldn’t work, since you need air flow to survive.
Now, the U.S. Centers for Disease Control and Prevention is actually recommending people wear cloth masks — not surgical masks or N95, which they recommend for health care workers only. The problem with this is that not only do cloth masks fail to provide any protection against aerosolized viruses, as noted above, they also provide very little protection in terms of blocking respiratory droplets.
As reported by The National Academies of Sciences in its Rapid Expert Consultation on the Effectiveness of Fabric Masks for the COVID-19 Pandemic report, published April 8, 2020:13
“The evidence from … laboratory filtration studies suggest that … fabric masks may reduce the transmission of larger respiratory droplets. There is little evidence regarding the transmission of small aerosolized particulates of the size potentially exhaled by asymptomatic or presymptomatic individuals with COVID-19.”
So, regardless of the mask, it will not prevent you from exhaling or inhaling the aerosolized virus, but cloth masks are clearly the least preferable option if you actually want to reduce the spread of infection, as their ability to block respiratory droplets is also limited.
In particular, masks with airflow valves on the front should be avoided, as the valve lets out unfiltered air, thus negating the small benefit you might expect from a mask.14
What We Learned From the Mask for Flu Policy
To put the mask controversy into some perspective, let’s compare it to what we learned from the masking for influenza controversy a couple of years back. In September 2018, the Ontario Nurses Association (ONA) won its second of two grievances filed against the Toronto Academic Health Science Network’s (TAHSN) “vaccinate or mask” (VOM) policy. As reported by the ONA:15
“These policies force nurses and other health-care workers to wear an unfitted surgical mask for the entirety of their shift if they choose not to receive the influenza vaccine.
After reviewing extensive expert evidence submitted by both ONA and St. Michael’s Hospital, which was the lead case for the TAHSN group, Arbitrator William Kaplan, in his September 6 decision,16 found that St. Michael’s VOM policy is ‘illogical and makes no sense’ and ‘is the exact opposite of being reasonable.’ In reaching this conclusion, Arbitrator Kaplan rejected the hospital’s evidence.
This is the second such win for ONA. In 2015, Arbitrator James Hayes struck down the same type of policy in an arbitration that included other Ontario hospitals across the province … Hayes found there was ‘scant evidence’ that forcing nurses to use masks reduced the transmission of influenza to patients.
Despite this clear ruling, the majority of TAHSN hospitals refused to follow the Hayes award and maintained their respective VOM policies. As a result, ONA was forced to litigate this matter again at St. Michael’s Hospital …
ONA’s well-regarded expert witnesses, including Toronto infection control expert Dr. Michael Gardam, Quebec epidemiologist Dr. Gaston De Serres, and Dr. Lisa Brosseau, an American expert on masks, testified that there was insufficient evidence to support the St. Michael’s policy and no evidence that forcing healthy nurses to wear masks during the influenza season did anything to prevent transmission of influenza in hospitals.
They further testified that nurses who have no symptoms are unlikely to be a real source of transmission and that it was not logical to force healthy unvaccinated nurses to mask.”
No Direct Evidence Masks Prevent Spread of Influenza
In summary, the ONA argued, and Kaplan agreed, that the rule forcing unvaccinated nurses to wear a surgical mask during flu season to protect patients from influenza was not supported by science and was most likely an attempt to drive up vaccination rates among staff.
TAHSN argued that “The wearing of face masks can serve as a method of source control of infected HCWs [health care workers] who may or may not have symptoms. Masks may also prevent unvaccinated HCWs from as yet unrecognized infected patients or visitors.”17 Like the previous arbitrator, Kaplan disagreed.
“I … find that the weight of scientific evidence said to support the VOM Policy on patient safety grounds is insufficient to warrant the imposition of a mask-wearing requirement for up to six months every year.
Absent adequate support for the freestanding patient safety purpose alleged, I conclude that the Policy operates to coerce influenza immunization and, thereby, undermines the collective agreement right of employees to refuse vaccination,” Kaplan wrote,18 adding that the TAHSN’s mask rule:
“… was made in the admitted absence of direct evidence that mask- wearing HCWs protected patients from influenza; but on the basis of ‘indirect evidence [that] suggests it does.’
The only fair words to describe the evidence advanced in support of the masking component of the VOM policy in the THASN report, and in this proceeding, are insufficient, inadequate, and completely unpersuasive.”
CDC Now Promotes Mask Wearing for Flu
Despite the lack of supporting science, in its current guidance19 on mask use to prevent the spread of influenza, the CDC calls for health care personnel to wear a surgical mask or fit-tested respirator whenever they’re within 6 feet of an influenza patient.
They also now recommend that anyone suspected of having influenza who enters a medical facility should wear a mask “at all times until they are isolated in a private room.”
The CDC does point out that “Masks are not usually recommended in non-healthcare settings,” and that “No recommendation can be made at this time for mask use in the community by asymptomatic persons, including those at high risk for complications, to prevent exposure to influenza viruses.” Still, they add that:
“If unvaccinated high-risk persons decide to wear masks during periods of increased respiratory illness activity in the community, it is likely they will need to wear them any time they are in a public place and when they are around other household members.”
When was the last time you wore a mask during influenza season? Never? Me either. Have you ever even heard the CDC recommend mask wearing to prevent the spread of influenza in previous years?
Surgical masks used in healthcare settings such as during surgery are meant to prevent bacterial infections, as bacteria are much larger than viruses.
What has changed is that the CDC is now suggesting mask wearing, both at home and in public during influenza season, might be a good idea. Where’s the evidence showing masks help prevent the spread of influenza?
Are masks an effective way to reduce the spread of respiratory illnesses, or are these mask recommendations just another strategy to make the public surrender to irrational medical tyranny that is likely to radically increase implementation of mandatory vaccination? Of course, these vaccinations would not just be for the flu but also COVID-19 once a vaccine becomes available.
Cloth Masks Offer False Sense of Security
April 1, 2020, the Center for Infectious Disease Research and Policy (CIDRAP) published a commentary20 by retired professor Lisa Brosseau, ScD, and Margaret Sietsema, Ph.D., assistant professor at the University of Illinois, arguing that mandates calling for the wearing of cloth masks or face coverings in public are “not based on sound data.” Both are experts on respiratory protection and infectious diseases. July 16, the following editor’s note was added to the article:
If masks help a little bit, I think they are a good idea in very crowded conditions. However, it is developing into an issue that the left, as usual, likes to use to exert control over others. Like Nadler admonishing others for not wear masks during is little partisan ambush of Barr… while his worthless paper dust mask hung off his chin (the top one).