Back To Reproduction Numbers -- Chinese Flu -- November 15, 2020

PSA: I am neither personally nor publicly worried about a shortage of cleaning products this time around but a word to the wise: start to stock up. A six-week supply of paper products would be a great place to start. Walmart is starting to count customers again. 

Here we go again:

 I guess some families are going to have to be broken up to adhere to the 5-person limit.

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The R0 Factor

I can't recall if we discussed this on the blog. I do remember discussing this in a sidebar conversation with a reader some months ago. 

One link:

• basic reproduction number for measles:

The basic reproduction number, R nought (R0), is defined as the average number of secondary cases of an infectious disease arising from a typical case in a totally susceptible population, and can be estimated in populations if pre-existing immunity can be accounted for in the calculation. 

R0 determines the herd immunity threshold and therefore the immunisation coverage required to achieve elimination of an infectious disease. 

As R0 increases, higher immunisation coverage is required to achieve herd immunity. In July, 2010, a panel of experts convened by WHO concluded that measles can and should be eradicated. Despite the existence of an effective vaccine, regions have had varying success in measles control, in part because measles is one of the most contagious infections. 

For measles, R0 is often cited to be 12–18, which means that each person with measles would, on average, infect 12–18 other people in a totally susceptible population ... We calculated median measles R0 values stratified by key covariates. We found that R0 estimates vary more than the often cited range of 12–18. 

R0, various sources, generally accepted:

• measles: 12 - 18
• chickenpox: 10 - 12
• seasonal flu (influenza, e.g., H1N1): 2 - 3
• Ebola: 1.7 - 2.0
• Chinese flu: 1.2

Basic reproduction number: wiki. 

From wiki and various other sources:

• measles, 12 - 18
• chickenpox: 10 - 12
• polio: 5 - 7
• smallpox: 3.5 - 6
• Chinese flu: 2- 6 (but still, probably too early to say for sure)
• seasonal flu / influenza: 1.4 - 1.6
• tuberculosis: 0.26 in the Netherlands; 4.3 in China;
  
• leprosy: below 1.0
  

The lower the R0 factor, the lower the percent required for "herd immunity."

The very, very low R0 factor for Chinese flu helps explain why even a family with one member getting infected, the others  do not become infected.

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Chinese Flu

November 15, 2020.

Link here: filter set to "yesterday."

Total cases / one million:

1. North Dakota at 8.3%
2. South Dakota at  7.3%
3. Iowa at 5.7%
4. Wisconsin at 5.2%
5. Nebraska at 5.0%

Reminder:

• Spanish flu, 1918 - 1920 -- estimated that 33% of global population infected with the virus.

#29. New York at 3.1%
#40. California at 2.6%

Bottom line: we've got a long way to go.

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Maybe What We Need ... Proven Technology ....