Many have wondered if Japan possessed an ”X-factor” that led to a low
COVID-19 death rate.
We note that the mask non-wearing rate in mid-March alone was predicted
to contribute up to 72% of variations in the number of deaths per
million1. In addition, there was a remarkable
difference in face mask wearing rates between Western countries and
Asian countries, especially in East Asian countries including
Japan1. The county’s policy for wearing a face mask
alone cannot explain this significant difference. For example, there is
a high rate of wearing face masks in Japan even though this practice has
never been declared mandatory. We speculate that cultural differences
may be the major reason.
Many Japanese wear surgical masks on a daily basis not with the purpose
of shedding infections or pollens but to achieve inscrutability, similar
to the Westerners wearing sunglasses.
It is referred to as ”mask dependency” in a number of
cases2. While people may wish to achieve anonymity,
they also want to avoid making others uncomfortable. Jack, Caldara, and
Schyns state, “whereas Western Caucasian internal representations
predominantly featured the eyebrows and mouth, East Asian internal
representations showed a preference for expressive information in the
eye region”3. This tendency may be the major reason
why it is considered rude to wear sunglasses among eastern Asians and
why wearing face masks among Westerners is considered suspicious, which
could be why the western population exhibits a low face mask wearing
rate.
Additionally, the Japanese generally remain silent while using public
transportation as loudness is a sign of rudeness in
Japan4. This may also contribute to the ”X-factor”
because a very high proportion of aerosols are exhaled from asymptomatic
individuals while speaking rather than breathing5. In
addition, the viral density of aerosols is expected to vary between
speaking and breathing as the origin of the aerosols is different.
Aerosols originating from the mouth may contain more virus than those
from the lungs in asymptomatic individuals.
Although face mask wearing has not yet been proven as an independent
risk factor of COVID-19 mortality, a high rate of mask wearing in Japan
may be the major candidate for the so called ”X-factor.”