Corona COVID-19 virus transmission and mitigation.
4 reasons why face masks are crucial (scroll to bottom of this page)
How does the COVID-19 virus spread?
In droplet form, the coronavirus is airborne for a few seconds after someone sneezes or coughs. It’s able to travel only a short distance before gravitational forces pull it down. Someone close enough for the virus particles to reach in that brief period can therefore be infected.
By wearing a face mask, the risk of these droplets emitted by others reaching our eyes, nose or eyes is much reduced. See this video for a test by Japanese researchers, showing how long mini droplets remain suspended in the air in enclosed spaces.
Anyone who comes into contact with virus-containing droplets that fall onto a surface is at risk of being infected too. The new coronavirus can survive on surfaces for several hours; hence the importance of hand-washing after touching a surface in a public place
Why do I need to wash my hands often?
It is surprising how long the virus survives on uncleaned surfaces. The table below gives the results of persistence testing on other, similar virus strains.
With these kinds of survival times in droplets on so many surfaces, it is understandable why the recommendation is to wash our hands often, and not touch our face after touching potentially infected surfaces.
How does the virus spread?
It appears there are two main ways in which the virus is transmitted:
- In droplet form, the coronavirus is airborne for a few seconds after someone sneezes or coughs. It’s able to travel only a short distance before gravitational forces pull it down. Someone close enough for the virus particles to reach in that brief period can therefore be infected.
- Via surfaces. Anyone who comes into contact with virus-containing droplets that fall onto a surface is at the risk of being infected. The new coronavirus can survive on surfaces for several hours; hence the importance of hand-washing after touching a surface in a public place.
Can the virus spread via the air?
An aerosol is a wholly different physical state: Particles are held in the air by physical and chemical forces. Fog is an aerosol; tiny water droplets are suspended in air. The particles remain suspended for hours or more, depending on factors such as heat and humidity. If virus particles, probably on droplets of mucus or saliva, could be suspended in air for more than a few seconds, as the measles virus can, then anyone passing through that pathogenic cloud could become infected.
There are strong reasons to doubt that the new coronavirus has anything close to that capability.
Other than via droplets, currently there appears to be little evidence that the virus can remain suspended by itself in the air (like e.g. the measles virus).
The complete article can be found here.
Why is touching my face not a good idea?
The easiest way for the virus to enter our body is via our mouth, nose and eyes. It is therefore that touching our face after our fingers have been in contact with a potentially infected surface increases the risk of introducing the virus.
Especially in view of the long persistence time of the virus in droplets on many surfaces, one should take care of touching surfaces in public places. And immediately washing hands afterwards.
How likely is that I am spreading the disease?
On average, it takes between five and six days between the moment of infection and the showing of symptoms. The incubation time can be as long as 14 days. Unfortunately, once I’m infected, even though I’m feeling perfectly fine, the virus can spread to others.
It is certain that 80 to 85% of the people infected show no or only mild symptoms. But they are still contagious while they are not aware of being a carrier.
Read the full article here.
How much virus will cause me to fall ill?
A healthy person’s immune system appears to have the ability to fight off small doses of the virus.
However, as the ‘case load’ of viruses in our body increases, so does the risk of developing symptoms.
This is the reason why gatherings of larger groups of people are prohibited. Catching a virus from one person is bad enough. But catching it from multiple people significantly increases the virus case load and reduces the ability of the immune system to fight it off.
The complete text can be found here.
How serious is having had Corona. Is it 'just' a severe flu?
Anecdotal evidence from Hong Kong appears to suggest that for a significant portion of patients who after treatment are discharged from the hospital suffer from permanent lung damage.
The virus attacks the lungs, and start an inflammatory process. This video shows clearly how that works. Pay attention to the yellow, inflamed spots. This patient is on an intubated ventilator.
The article appears here.
Why are workers in the health care sector wearing protective glasses?
Since the virus is transmitted via airborne droplets and the virus can enter via the eyes, it is a good idea to protect the eyes from exposure. Wearing protective ‘anti-splash’ glasses adds additional protection.
Such anti-splash goggles would be a good idea too for anyone who is out and gets close to other people.
In view of all of this, why is wearing a face mask appropriate?
There are a few good reasons to wear a mask:
- It makes it less likely we will inhale an airborne droplet which contains the virus.
- It makes it less likely that when we cough or sneeze, that droplets exit from our nose and mouth, thus protecting others around us.
- Since our mouth and nose are not exposed, it makes it less likely that we will be touching them with our fingers.
- Even though a mask will not offer 100% protection, it will add significant protection with a higher chance of keeping any virus case load to a level where our immune system can cope with it.