How COVID-19 Spreads

 

Back in March I presented the above graphic. Nothing too innovative. My grandmother spent a decade at Sea View Hospital in New York City managing TB and Spanish Flu patients. Wash your hands, don't touch your face, cover your mouth, don't touch things. She survived. I think I learned a lesson. But there was no scientific evidence just decades of experience.

Along comes the CDC. They now state:

COVID-19 is thought to spread mainly through close contact from person-to-person. Some people without symptoms may be able to spread the virus. We are still learning about how the virus spreads and the severity of illness it causes.

Person-to-person spread: The virus is thought to spread mainly from person-to-person.

 1. Between people who are in close contact with one another (within about 6 feet).

2. Through respiratory droplets produced when an infected person coughs, sneezes, or talks.

3. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs.

4. COVID-19 may be spread by people who are not showing symptoms.

 The virus spreads easily between people: How easily a virus spreads from person-to-person can vary. Some viruses are highly contagious, like measles, while other viruses do not spread as easily. Another factor is whether the spread is sustained, which means it goes from person-to-person without stopping. The virus that causes COVID-19 is spreading very easily and sustainably between people. Information from the ongoing COVID-19 pandemic suggests that this virus is spreading more efficiently than influenza, but not as efficiently as measles, which is highly contagious. In general, the more closely a person interacts with others and the longer that interaction, the higher the risk of COVID-19 spread.

 The virus may be spread in other ways: It may be possible that a person can get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or possibly their eyes. This is not thought to be the main way the virus spreads, but we are still learning more about how this virus spreads.

 Now is this not what we said in March? This is the nth revision of the CDC assessment. There seems to be a serious and chronic problem there. One wonders when it can and must be corrected?

As an added note, as we had also discussed, the virion travels in an encased  aerosol, namely an air filled water encased bubble that moves about with Newtons laws of motion as well as following Archimedes principle. The aerosol also has thermodynamic effects as well as Brownian motion effects. Thus aerosols "linger" depending upon a multiplicity of factors. Just what makes for lingering aerosols depends. ( see Seinfeld and Pandis, Atmospheric Chemistry and Physics, Wiley, 2016, Chapters 9-10) There is a significant body of knowledge in atmospheric aerosols but virion containing ones, not so much.

What is lacking is good quality physical and clinical research. Unfortunately the CDC does not seem as advance as my grandmother back in 1918.