World Monitor Magazine, №1/2020 WM_March 2020_FOR WEB (12.03.) | Page 43

additional content
COVID-19:
WHY WE SHOULD ALL WEAR MASKS —
THERE IS NEW SCIENTIFIC RATIONALE
The official recommendation in the United States (and other Western countries) that the public
should not wear face masks was motivated by the need to save respirator masks for health care
workers. There is no scientific support for the statement that masks worn by non-professionals
are “not effective”. In contrary, in view of the stated goal to “flatten the curve”, any additional,
however partial reduction of transmission would be welcome — even that afforded by the simple
surgical masks or home-made (DIY) masks (which would not exacerbate the supply problem). The
latest biological findings on SARS-Cov-2 viral entry into human tissue and sneeze/cough-droplet
ballistics suggest that the major transmission mechanism is not via the fine aerosols but large
droplets, and thus, warrant the wearing of surgical masks by everyone.
The surgeon general tweeted: “STOP BUYING MASK, they
are not effective…”. The Center for Disease Controls (CDC)
states that surgical masks offer far less protection than the
N95 respirator masks (which also must be perfectly fitted
and only professionals can do it). The CDC recommends that
healthy persons should not wear masks at all, only the sick
ones. These guidelines are not rooted in scientific rationales
but were motivated by the need to save the valuable masks
for health professionals in view of a shortage. But they may
have had unintended consequences: stigmatizing those that
wear masks in the public (you are a hoarder, or you are con-
tagious!)
Contrast this with the cultural habit, the encouragement, or
even mandate to wear masks in Asian countries — which
have now “flattened the curve” or even have had a flatter
curve from the beginning.
Sure, surgical masks, and improperly worn N95 respirator
masks, do not offer perfect protection. But if the stated goal
is to “flatten” the curve (as opposed to eradication of the
virus), we have to abandon the black-and-white thinking, and
embrace shades of grey. We cannot any longer claim that
masks “are not effective”. We cannot allow the perfect to be
the enemy of the good. What if a however partial protection
afforded by leaky surgical or even self-made masks reduces
transmission probability to an extent that is similar to that
of the recommended (equally imperfect) distancing by more
than 6 feet from each other or “not touching your face”? It
could then double the impact of non-pharmacological inter-
vention (NPI) on flattening the curve (FIG. 1).
FIGURE 1. “Flattening the curve”. Effect of mitigating inter-
ventions that would decrease the initial reproduction rate
R0 by 50% when implemented at day 25. Red curve is the
course of numbers of infected individuals (”case”) without
intervention. Green curve reflects the changed (”flattened”)
curve after intervention. Day 0 (March 3, 2020) is the time
at which 100 cases of infections were confirmed (d100 = 0).
The model is only for illustration and was performed in the
SEIR-model simulator (http://gabgoh.github.io/COVID/index.
html). The non-intervention model was fitted to these data
points: a time period of twenty days in which the number of
cases in the United States has risen from 100 (d100=0) to
35,000 (d100=20). Standard parameters were used (popula-
tion size 330 M, Tinc=5.2 days, Tinf = 3.0 days but with the
rather high value R0=5.6 in order to achieve the observed
rate of increase of case numbers in the U.S. The curves are
redrawn not to scale.