Posted 20200420
I'm not a doctor. I don't have
anything more than an analytical mind that looks at data. If you want to ignore
this, please do. I an not trying to start any fights. I point out incredibly
bad conclusions being drawn regarding by supposed experts regarding public
wearing of masks.
There are two articles of note here.
One is COMMENTARY (Says so right on it), but it is a professional medical
research group that recommends against requiring mask wearing in public:
Here is a direct quote:
We do not
recommend requiring the general public who do not have symptoms of
COVID-19-like illness to routinely wear cloth or surgical masks because:
·
There is no scientific evidence they are effective in reducing the
risk of SARS-CoV-2 transmission
·
Their use may result in those wearing the masks to relax other
distancing efforts because they have a sense of protection
·
We need to preserve the supply of surgical masks for at-risk
healthcare workers.
Sweeping
mask recommendations—as many have proposed—will not reduce SARS-CoV-2
transmission, as evidenced by the widespread practice of wearing such masks in
Hubei province, China, before and during its mass COVID-19 transmission
experience earlier this year. Our review of relevant studies indicates that
cloth masks will be ineffective at preventing SARS-CoV-2 transmission, whether
worn as source control or as PPE.
End quote
Here is
article two:
This article agrees with the first article on one specific
point. Untreated masks do not prevent
mortality. 100% of mice presented with virus infected air on untreated
masks died within two weeks. Here is the graph:
So point 1 is true for bare masks.
Point 1 is false (a binary false in this experiment - all mice survived) when
using a salt treated mask. Note - the virus used in this study (2017) were two
SARS viruses. Similar, but not identical, to COVID.
Look at this graph taken today (20200417)
from:
Countries that are compelling
because of their absence:
Japan (pop 127 million)
South Korea (pop 51 million)
On a per capita basis, both of these
countries should be on here. They are not. I am not presupposing to say the
prevalent use of masks in these cultures is the only effect, but it is clearly
bad science to make point #1 above: There is no scientific evidence they
are effective in reducing the risk of SARS-CoV-2 transmission. There is at
least anecdotal evidence, and I am confident that with an afternoon of thought,
I could make a fairly quantifiable justification of that based on this data
alone. There are likely other contributors, but ignoring the cultural bias
associated with the expectation to wear masks in these areas seems to be
ignoring an important epidemiological fact.
Further note, I will bet the vast
majority of the mask wearing people in Japan and South Korea are not using
salt treatment. So given #1 (I'm stipulating bare mask don't help the wearer),
how do you account for the lack of representation by Japan and South Korea on
this? Masks are effective in preventing the
spread of the virus by infected people.
The authors arguing against use of
masks by the public state:
Cloth masks as source
control
A
historical overview of cloth masks notes their use in US healthcare settings
starting in the late 1800s, first as source control on patients and nurses and
later as PPE by nurses.20
Kellogg,21 seeking
a reason for the failure of cloth masks required for the public in stopping the
1918 influenza pandemic, found that the number of cloth layers needed to
achieve acceptable efficiency made them difficult to breathe through and caused
leakage around the mask. We found no well-designed studies of cloth masks as
source control in household or healthcare settings.
In sum,
given the paucity of information about their performance as source control in
real-world settings, along with the extremely low efficiency of cloth masks as
filters and their poor fit, there is no evidence to support their use by the
public or healthcare workers to control the emission of particles from the
wearer.
They
could not find a study? Sloppy and lazy. I think I can run an experiment in
three days with the right equipment (need a DOP* generator and reader) that
could make a reasonable argument to demonstrate source control effectiveness:
1.
Determine volume of a cough. (not new science here, I'm guessing)
2. Put a
trace contaminant (e.g. DOP* used in HEPA filter test). Measure the amount "released"
by a surge expression of the cough volume with no mask.
3. Repeat
with a cloth face mask.
I'm
willing to wager large sums of money on two facts:
1.
Contamination will be found in both expressions.
2. Less
contamination will be found on the one using a face mask. And large variations
in amounts will be measured based on fit, number of layers, and material.
USEFUL
science would do the above and provide data that states, for example, (this is
an e.g., not a statement of fact): Two layers of t shirt cotton used as a mask
with reasonably tight adherence to the face result in a 50% reduction in
the amount of contaminant detected in the expressed volume. Then we can have
the argument about whether a 50% source reduction is worth making a regulation
over it.
It is incredibly bad science for the
authors in paper one to draw the conclusions they did based on a study of
particulate efficiency. This is a classic example of the loss of expertise we
are suffering in STEM areas, and the corresponding loss of belief in experts by
society. These are cause and effect.
This is not an argument in favor or
in opposition to "opening the country". This is my attempt to inform
you that you can do something to both reduce your chance of infecting others
and reduce your chance of getting sick. Wear a salt brine infused mask when in
public. All the cool kids do...
Thanks for reading!
All the best,
Brian
*DOP = dioctyl (2-ethyl hexyl)
phthalate (DOP) - used in HEPA filter testing.
No comments:
Post a Comment