Dental Asia January/February 2024

CLINICAL FEATURE
Fig. 2: Masks stop viruses much like this strainer collects sand
While this phenomenon might be
one reason why the role of airborne
transmissions in hospital infections
and from dental and orthopedic
aerosols remains debatable, it serves
to question the necessity of masks. 3,4
SIZE MATTERS
A nanometer is one billionth of a
metre. A strand of human hair is
approximately between 80,000-
100,000nm wide. The influenza and
coronaviruses range from 80-120nm,
or approximately 0.1µm in diameter.
This means that approximately 1,000
of these viruses would fit across the
width of a human hair. 5,6 The best
fitting mask will not prevent a single
human hair from passing between it
and the face.
N95 mask fabrics are designed to
filter out 95% of airborne particles
provided they are larger than 0.3µm
in diameter and most surgical mask
materials filter out particles 2.5µm or
larger. 7 Therefore, its effectiveness
in filtering out viruses of 0.1µm in
diameter is highly questionable. Even
if such devices did impede the flow of
influenza and coronaviruses, millions
of stray viruses would continue to pass
through the gaps present around the
periphery of masks.
In practical terms this means that a
mask is no more effective at stopping
viruses than a strainer is at collecting
sand (Fig. 2).
HISTORICAL PERSPECTIVE
Beginning with studies from 1946,
a meta-analysis of masks efficacy
published in February 2020 concluded
that surgical-type face masks were
not effective in reducing influenza
transmissions. 8
In 2013, nurses from Ontario, Canada,
filed a grievance against the use
of masks in lieu of receiving a flu
vaccination. Independent arbitrators
in 2015 and 2018 reviewed hundreds
of relevant documents and found
that hospitals could not force mask
mandates because supporting
evidence was insufficient, inadequate,
and completely unpersuasive. 9,10
In 2017 the Centers for Disease
Control and Prevention (CDC) compiled
a report based on a 16-year study of
almost 200 articles concerning nonpharmaceutical
methods of mitigating
the effects of influenza pandemics.
Masks were not mentioned — attesting
to the CDC’s recognition of its
ineffectiveness. 11
The World Health Organization (WHO)
in 2019, while commenting on the use
of non-pharmaceutical measures to
avoid respiratory transmissions, noted
that: “There is also a lack of evidence
for the effectiveness of improved
respiratory etiquette and the use of
face masks in community settings
during influenza epidemics and
pandemics.” 12
In a March 2020 interview on the ’60
minutes’ news programme, Dr Anthony
Fauci stated categorically that “there
is no reason to be walking around
wearing a mask”. 13
The large randomised DANMASK-19
study released in 2021 concluded that
surgical masks did not reduce SARS-
CoV-2 infection rates among wearers in
a community setting. 14
This is but a small sample of the
decades of studies refuting mask
efficacy. For more extensive reviews,
readers are referred to: ‘The Mask
Studies You Should Know’ 15 and ‘More
than 170 Comparative Studies and
Articles on Mask Ineffectiveness and
Harms’. 16
REAL WORLD DATA
In his 2022 book, UNMASKED: The
Global Failure of COVID Mask Mandates,
Ian Millar provides numerous graphs
from around the world comparing
unmasked and masked populations (Fig.
3). These real-world experiences show
no appreciable differences in COVID
infection rates among the two groups. 17
HARMS
A fundamental tenet of health care is:
“First, do no harm”. This applies not only
to the delivery of healthcare but also
to measures taken to mitigate disease
transmission, including the use of
masks.
Fig. 3: Mask wearing results in no appreciable difference in the
number of COVID-19 cases
34 DENTAL ASIA JANUARY / FEBRUARY 2024