Posted By Colleen Huber, NMD via PrimaryDoctor July 14, 2020
At this writing, there is a recent surge in widespread use by the public of facemasks when in public places, including for extended periods of time, in the United States as well as in other countries. The public has been instructed by media and their governments that one’s use of masks, even if not sick, may prevent others from being infected with SARS-CoV-2, the infectious agent of COVID-19.
(Editor's Note: This YouTube presentation was in no way offensive. It was an intelligent and well done presentation of the facts, but it didn't fit the "masks, lockdown and distancing" narrative promoted by the media. This is just another case of left wing media censorship. I wished I had some way of saving this video, as I would have re-linked it. RK)
A review of the peer-reviewed medical literature
examines impacts on human health, both immunological, as well as
physiological. The purpose of this paper is to examine data regarding
the effectiveness of facemasks, as well as safety data. The reason that
both are examined in one paper is that for the general public as a
whole, as well as for every individual, a risk-benefit analysis is
necessary to guide decisions on if and when to wear a mask.
Are masks effective at preventing transmission of respiratory pathogens?
In
this meta-analysis, face masks were found to have no detectable effect
against transmission of viral infections. (1) It found: “Compared to no
masks, there was no reduction of influenza-like illness cases or
influenza for masks in the general population, nor in healthcare
workers.”
This 2020 meta-analysis found that
evidence from randomized controlled trials of face masks did not support
a substantial effect on transmission of laboratory-confirmed influenza,
either when worn by infected persons (source control) or by persons in
the general community to reduce their susceptibility. (2)
Another
recent review found that masks had no effect specifically against
Covid-19, although facemask use seemed linked to, in 3 of 31 studies,
“very slightly reduced” odds of developing influenza-like illness. (3)
This
2019 study of 2862 participants showed that both N95 respirators and
surgical masks “resulted in no significant difference in the incidence
of laboratory confirmed influenza.” (4)
This 2016
meta-analysis found that both randomized controlled trials and
observational studies of N95 respirators and surgical masks used by
healthcare workers did not show benefit against transmission of acute
respiratory infections. It was also found that acute respiratory
infection transmission “may have occurred via contamination of provided
respiratory protective equipment during storage and reuse of masks and
respirators throughout the workday.” (5)
A 2011
meta-analysis of 17 studies regarding masks and effect on transmission
of influenza found that “none of the studies established a conclusive
relationship between mask/respirator use and protection against
influenza infection.” (6) However, authors speculated that
effectiveness of masks may be linked to early, consistent and correct
usage.
Face mask use was likewise found to be not
protective against the common cold, compared to controls without face
masks among healthcare workers. (7)
Airflow around masks
Masks
have been assumed to be effective in obstructing forward travel of
viral particles. Considering those positioned next to or behind a mask
wearer, there have been farther transmission of virus-laden fluid
particles from masked individuals than from unmasked individuals, by
means of “several leakage jets, including intense backward and downwards
jets that may present major hazards,” and a “potentially dangerous
leakage jet of up to several meters.” (8)
All masks were thought to reduce forward airflow by 90% or more over wearing no mask. However, Schlieren imaging showed that both surgical masks and cloth masks had farther brow jets (unfiltered upward airflow past eyebrows) than not wearing any mask at all, 182 mm and 203 mm respectively, vs none discernible with no mask. Backward unfiltered airflow was found to be strong with all masks compared to not masking.
All masks were thought to reduce forward airflow by 90% or more over wearing no mask. However, Schlieren imaging showed that both surgical masks and cloth masks had farther brow jets (unfiltered upward airflow past eyebrows) than not wearing any mask at all, 182 mm and 203 mm respectively, vs none discernible with no mask. Backward unfiltered airflow was found to be strong with all masks compared to not masking.
For
both N95 and surgical masks, it was found that expelled particles from
0.03 to 1 micron were deflected around the edges of each mask, and that
there was measurable penetration of particles through the filter of each
mask. (9)
Penetration through masks
A
study of 44 mask brands found mean 35.6% penetration (+ 34.7%). Most
medical masks had over 20% penetration, while “general masks and
handkerchiefs had no protective function in terms of the aerosol
filtration efficiency.” The study found that “Medical masks, general
masks, and handkerchiefs were found to provide little protection against
respiratory aerosols.” (10)
It may be helpful to
remember that an aerosol is a colloidal suspension of liquid or solid
particles in a gas. In respiration, the relevant aerosol is the
suspension of bacterial or viral particles in inhaled or exhaled breath.
In another study, penetration of cloth masks by particles was almost 97% and medical masks 44%. (11)
N95 respirators
Honeywell
is a manufacturer of N95 respirators. These are made with a 0.3 micron
filter. (12) N95 respirators are so named, because 95% of particles
having a diameter of 0.3 microns are filtered by the mask forward of the
wearer, by use of an electrostatic mechanism. Coronaviruses are
approximately 0.125 microns in diameter.
This
meta-analysis found that N95 respirators did not provide superior
protection to facemasks against viral infections or influenza-like
infections. (13) This study did find superior protection by N95
respirators when they were fit-tested compared to surgical masks. (14)
This study found that 624 out of 714 people wearing N95 masks left visible gaps when putting on their own masks. (15)
Surgical masks
This
study found that surgical masks offered no protection at all against
influenza. (16) Another study found that surgical masks had about 85%
penetration ratio of aerosolized inactivated influenza particles and
about 90% of Staphylococcus aureus bacteria, although S aureus particles
were about 6x the diameter of influenza particles. (17)
Use
of masks in surgery were found to slightly increase incidence of
infection over not masking in a study of 3,088 surgeries. (18) The
surgeons’ masks were found to give no protective effect to the patients.
Other studies found no difference in wound infection rates with and without surgical masks. (19) (20)
This
study found that “there is a lack of substantial evidence to support
claims that facemasks protect either patient or surgeon from infectious
contamination.” (21)
This study found that medical masks have a wide range of filtration efficiency, with most showing a 30% to 50% efficiency. (22)
Specifically,
are surgical masks effective in stopping human transmission of
coronaviruses? Both experimental and control groups, masked and
unmasked respectively, were found to “not shed detectable virus in
respiratory droplets or aerosols.” (23) In that study, they “did not
confirm the infectivity of coronavirus” as found in exhaled breath.
A
study of aerosol penetration showed that two of the five surgical masks
studied had 51% to 89% penetration of polydisperse aerosols. (24)
In
another study, that observed subjects while coughing, “neither surgical
nor cotton masks effectively filtered SARS-CoV-2 during coughs by
infected patients.” And more viral particles were found on the outside
than on the inside of masks tested. (25)
Cloth masks
Cloth
masks were found to have low efficiency for blocking particles of 0.3
microns and smaller. Aerosol penetration through the various cloth
masks examined in this study were between 74 and 90%. Likewise, the
filtration efficiency of fabric materials was 3% to 33% (26)
Healthcare
workers wearing cloth masks were found to have 13 times the risk of
influenza-like illness than those wearing medical masks. (27)
This
1920 analysis of cloth mask use during the 1918 pandemic examines the
failure of masks to impede or stop flu transmission at that time, and
concluded that the number of layers of fabric required to prevent
pathogen penetration would have required a suffocating number of layers,
and could not be used for that reason, as well as the problem of
leakage vents around the edges of cloth masks. (28)
Masks against Covid-19
The New England Journal of Medicine editorial on the topic of mask use versus Covid-19 assesses the matter as follows:
“We
know that wearing a mask outside health care facilities offers little,
if any, protection from infection. Public health authorities define a
significant exposure to Covid-19 as face-to-face contact within 6 feet
with a patient with symptomatic Covid-19 that is sustained for at least a
few minutes (and some say more than 10 minutes or even 20 minutes).
The chance of catching Covid-19 from a passing interaction in a public
space is therefore minimal. In many cases, the desire for widespread
masking is a reflexive reaction to anxiety over the pandemic.” (29)
Are masks safe?
During walking or other exercise
Surgical mask wearers had significantly increased dyspnea after a 6-minute walk than non-mask wearers. (30)
Researchers
are concerned about possible burden of facemasks during physical
activity on pulmonary, circulatory and immune systems, due to oxygen
reduction and air trapping reducing substantial carbon dioxide
exchange. As a result of hypercapnia, there may be cardiac overload,
renal overload, and a shift to metabolic acidosis. (31)
Risks of N95 respirators
Pregnant
healthcare workers were found to have a loss in volume of oxygen
consumption by 13.8% compared to controls when wearing N95 respirators.
17.7% less carbon dioxide was exhaled. (32) Patients with end-stage
renal disease were studied during use of N95 respirators. Their partial
pressure of oxygen (PaO2) decreased significantly compared to controls
and increased respiratory adverse effects. (33) 19% of the patients
developed various degrees of hypoxemia while wearing the masks.
Healthcare
workers’ N95 respirators were measured by personal bioaerosol samplers
to harbor influenza virus. (34) And 25% of healthcare workers’
facepiece respirators were found to contain influenza in an emergency
department during the 2015 flu season. (35)
Risks of surgical masks
Healthcare workers’ surgical masks also were measured by personal bioaerosol samplers to harbor for influenza virus. (36)
Various
respiratory pathogens were found on the outer surface of used medical
masks, which could result in self-contamination. The risk was found to
be higher with longer duration of mask use. (37)
Surgical
masks were also found to be a repository of bacterial contamination.
The source of the bacteria was determined to be the body surface of the
surgeons, rather than the operating room environment. (38)
Given that surgeons are gowned from head to foot for surgery, this finding should be especially concerning for laypeople who wear masks. Without the protective garb of surgeons, laypeople generally have even more exposed body surface to serve as a source for bacteria to collect on their masks.
Given that surgeons are gowned from head to foot for surgery, this finding should be especially concerning for laypeople who wear masks. Without the protective garb of surgeons, laypeople generally have even more exposed body surface to serve as a source for bacteria to collect on their masks.
Risks of cloth masks
Healthcare
workers wearing cloth masks had significantly higher rates of
influenza-like illness after four weeks of continuous on-the-job use,
when compared to controls. (39)
The increased rate
of infection in mask-wearers may be due to a weakening of immune
function during mask use. Surgeons have been found to have lower oxygen
saturation after surgeries even as short as 30 minutes. (40) Low
oxygen induces hypoxia-inducible factor 1 alpha (HIF-1). (41) This in
turn down-regulates CD4+ T-cells. CD4+ T-cells, in turn, are necessary
for viral immunity. (42)
In the summer of 2020 the United States is experiencing a surge of popular mask use, which is frequently promoted by the media, political leaders and celebrities. Homemade and store-bought cloth masks and surgical masks or N95 masks are being used by the public especially when entering stores and other publicly accessible buildings. Sometimes bandanas or scarves are used. The use of face masks, whether cloth, surgical or N95, creates a poor obstacle to aerosolized pathogens as we can see from the meta-analyses and other studies in this paper, allowing both transmission of aerosolized pathogens to others in various directions, as well as self-contamination.
Weighing risks versus benefits of mask use
In the summer of 2020 the United States is experiencing a surge of popular mask use, which is frequently promoted by the media, political leaders and celebrities. Homemade and store-bought cloth masks and surgical masks or N95 masks are being used by the public especially when entering stores and other publicly accessible buildings. Sometimes bandanas or scarves are used. The use of face masks, whether cloth, surgical or N95, creates a poor obstacle to aerosolized pathogens as we can see from the meta-analyses and other studies in this paper, allowing both transmission of aerosolized pathogens to others in various directions, as well as self-contamination.
It must also be
considered that masks impede the necessary volume of air intake required
for adequate oxygen exchange, which results in observed physiological
effects that may be undesirable. Even 6- minute walks, let alone more
strenuous activity, resulted in dyspnea. The volume of unobstructed
oxygen in a typical breath is about 100 ml, used for normal
physiological processes. 100 ml O2 greatly exceeds the volume of a
pathogen required for transmission.
The foregoing
data show that masks serve more as instruments of obstruction of normal
breathing, rather than as effective barriers to pathogens. Therefore,
masks should not be used by the general public, either by adults or
children, and their limitations as prophylaxis against pathogens should
also be considered in medical settings.
Endnotes
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Endnotes
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