So we are many months into a pandemic and people are tired
and stressed out and so many are worried about the future. It has been my experience that one of the
best ways to decrease worry is to take action.
So I have some action steps that we can all take to help relieve worry
right now. I will be sharing these in a
series of blog posts.
The Great Mask Debate
Protect yourself with a mask and social distancing whenever
possible. There has been much
controversy surrounding mask wearing. The
purpose of wearing masks is to reduce the spread of infection through droplets
and aerosols as these particles can contain infectious materials. Droplets and aerosols are naturally produced
by the respiratory system and are released from our mouths and noses whenever
we breathe, cough, sneeze, talk or sing.
We know this because as children
we were taught to cover our mouth and nose when we cough or sneeze. The droplets are heavier and are pulled down
by gravity which is why distancing can be helpful. Aerosols (very small particles) float in the
air for a period up to several hours and spread like smoke through a closed
space.
Aside from fit-tested N95 masks, masks provide limited
protection for the wearer because some droplets and aerosols can get around the
gaps in the sides of the masks. You
might ask yourself why, in light of that information, should anyone bother
wearing a mask? Have we all not heard
about (perhaps on social media) somebody who always wore a mask and still got
sick? Masks are more effective in protecting
others by reducing the droplets and aerosols that the wearer releases into the
air. If we have widespread mask usage the amount of
infectious viral particles being released is greatly reduced. The number of infectious particles is one
important aspect in spread of a disease.
Per an article published in October 2020 in the journal Nature,
surgical masks and comparably constructed fabric masks reduce aerosol expulsion
by about 67% and N95 masks reduce 90% of aerosols expelled. That study goes into much more detail
looking at 14 different mask materials and it makes for interesting reading if
you are interested.
Masks with a vent and fabric neck gaiters are explicitly not
effective and should not be used. The
vents allow droplets to exit and the neck gaiters have been shown to increase
risk by aerosolizing the droplets (making them into very small and more mobile
particles). The clear plastic face
shields are really not effective at preventing droplet transmission as the
droplets pass right around the shield. I
have seen these clear plastic shields mounted on a headband and also advertised
as masks with a mask-like shape and having earpieces like glasses to hold it
against the face. None of those clear
shields are effective.
All this data means that by wearing a mask a
potentially-infected individual will release fewer droplets into the
surrounding area. That decreases the
potential for infecting others. If we
have all or nearly all persons wearing masks when out in public and everyone’s
droplet release potential is decreased and we’ve significantly decreased the
risk of disease transmission. When considering
the disease-causing capability of an organism we have to consider the
characteristics of the organism, the health of the host and the number of the
organisms released. Wearing masks
decreases the release of disease-causing organisms. Other articles point out that the size of
the holes in masks are much larger than the virus itself. This is also true. Viruses travel in droplets and sometimes in
smaller particles called respiratory nuclei.
These droplets are larger than the virus itself and so may be trapped by
the mask. It is important to practice proper masking
protocol which means limit handling of the mask and dispose of the mask (or wash
it if it is a fabric mask) after it has been worn for a length of time. Bacteria can certainly collect on the mask
so these hygiene measures are important.
Masks of any kind must cover the mouth and nose as droplets are released
into the air by both mouth and nose and if there is a metal nosepiece it should
be bent around the nose for optimal fit.
It is unnecessary to wear a mask if you are alone in your vehicle, although
I always put mine on if I am in line at the coffee shop drive-through and need
to interact with the employees to receive my order. It is not necessary to wear them if you are
outside away from others as the droplets you are releasing will be quickly
dispersed in the outside air. Indoor
ventilation systems allow the droplets and aerosols to linger which is why
masking is important indoors. I have
read some interesting articles about advances in indoor air quality management
which look wonderful so that would be a nice positive development from this
challenging situation.
One study that came out in April in the Annals of Internal
Medicine purported to show that masking was ineffective. It has since been retracted. Early in the pandemic there were so many
unknowns that it is not surprising that some of the early findings were
determined to be incomplete or incorrect.
Much of the hesitancy for masking recommendations on the part of the WHO
and CDC was related to supply issues for healthcare workers. We have learned so much since then and there
are masks in fashion patterns and instructions for mask making all over the
internet. With these options the
depletion of mask supply is no longer a concern. The fitted N95 masks are still best saved
for the healthcare staff as there are so many workable options available to the
public. See the October article in
Nature for some comparisons of materials.
A brief note about masks and children
The literature is generally in agreement that very young
children (2 -3 years of age and younger) should not be masked due to the risk
of suffocation. The American Academy of
Pediatrics and the Italian Pediatric Society have published statements about
masking in children and recommend masking for children older than 2 (the American
Academy of Pediatrics) or 3 (The Italian Pediatric Society). It would be a good idea to check with your
pediatrician if you have concerns about your children.
Common mask objections:
Can masks cause decreased blood levels of oxygen,
increased carbon dioxide levels? There
is no evidence of this and indeed studies have been performed using pulse oximeters
to measure levels during daily activities and exercise. Pulse oximeters, devices that measure blood oxygen levels, can be found very
inexpensively online and you can wear one while masked to check this out for
yourself.
Viral particles are way too small to be blocked by mask –
so using a mask to block them is like trying to block mosquitoes with a chicken
wire fence. I have seen this exact
argument on social media. As we
mentioned before viral particles do not travel by themselves. Viruses need a host and those particles are
expelled in droplets or aerosols.
My friend contracted the virus even though they wore a
mask. As mentioned above masks do
not provide 100% protection and they are more effective at protecting from
release of particles rather than blocking inhalation of particles in the
environment. Partial protection is
better than no protection.
Masking decreases the immune system activity – it’s like
living in a bubble so my immune system will be weakened. The immune system is indeed stimulated by
contact with environmental materials. A
partial block of environmental materials, such as a mask provides, does not
dampen immune system activity. You are
still being exposed to materials by touch, through food and beverage and even
in your own home.