The transmission of this virus
is primarily through respiratory droplets
produced by coughing, sneezing or talking
must directly contact the uninfected
individuals mucous membranes,
which limits the transmission zone
to around two meters.
Airborne transmission is caused by
the aerosolization of respiratory droplets
that can remain suspended
in the air over time.
This mechanism is less common
and usually associated
with enclosed poorly ventilated spaces.
Other considerations include universal
airborne precautions during any aerosol
generating medical procedures,
such as intubation
Other less common modes include surface
transmission, where touching
a contaminated surface
allows the virus to infect the individual
when they subsequently touch their eyes,
nose or mouth.
The virus can remain viable on hands
for up to 9 hours,
so handwashing is extremely important.
The virus survivability varies
based on surface type and environment
for porous surfaces like paper,
the virus becomes undetectable in minutes
to hours, while non-porous surfaces
may allow the virus to remain viable
for up to days.
Disinfectants and UV light are both
helpful within activation of the virus
and should be used to decrease
the viral load in high traffic areas.
Ambient environmental factors
such as temperature, humidity
and the size of the initial viral
inoculum also can influence
the survivability of the virus
Non respiratory specimen transmission
from stool blood products, semen or ocular
secretions remain unlikely, though
they cannot be definitively excluded.
Congenital infections have been
documented, but also remain very rare.
the virus has been identified in several
animal species, they are not considered
to be a major source of infection.
So, it is unfortunate, that this virus is so
infectious because it is also quite deadly
and in fact, in both these
entities infectivity and mortality,
it is far worse than influenza virus,
which we know causes an
annual epidemic of disease.
Why is this so?
Well, there are there are features involving,
asymptomatic but infected individuals, in whom,
the viral loads peak well before symptom onset.
So, that means that the individual who is infected
and is either asymptomatic
completely or pre-symptomatic,
will still have a high viral load
expressed in their respiratory droplets
and thus, be quite contagious.
As well, asymptomatic and
symptomatic patients all transmit
the same high viral loads
for the same length of time.
So, unfortunately, the symptom onset
which most of us use as an indicator
to self-isolate or put on gloves or a mask,
is unfortunately not the indicator,
that we think that it could be.
The other difference however,
is that, evolving variants
or mutant variants of the SARS Coronavirus II,
are having increased infectivity.
The infectivity of each new variant
has subsequently increased
from the original Wuhan strain in 2019.
So, as always, and especially in the
setting of this particular virus,
the science surrounding what we
know about transmission virus,
continues to evolve as does the virus itself.
Nature is quite active and as further
variants and mutant variants emerge,
so too will our understanding
of this particular virus
and how contagious it might be.
The mechanism of this increased
transmissibility is likely multifactorial.
We know mutations can allow the virus
to evade the immune system,
specifically in individuals
vaccinated against other variants.
Mutations can also allow for faster
viral replication rates in the bronchi,
increasing the viral load of respiratory
They've also developed mechanisms
to bind more tightly to human cells,
allowing faster membrane fusion
between infected and uninfected cells.