Let us summarize some key facts:
1. COVID-19 is a single stranded enveloped positive RNA virus of about 29,000 bases.
2. The virus enters the patient via nasal passages
3. The virus is aerosolized by infected individuals with or without symptoms.
4. It appears that transfer is dominated by hand contact with infected surfaces and then hand transfer to the nasophyranx.
5. The latency period is about 10 days until symptoms arise.
6. Symptoms may vary dramatically. This is a serious problem for the near asymptomatic are carriers.
7. We are assuming that once free from symptoms that there are viral antibodies which will inhibit secondary infections.
Now models are complex and prone to error. A model for New York is not a model for Boston. In a recent piece in Science the writer notes:
Models are at their most useful when they identify something that is not obvious, Kucharski says. One valuable function, he says, was to flag that temperature screening at airports will miss most coronavirus-infected people. There’s also a lot that models don’t capture. They cannot anticipate, say, the development of a faster, easier test to identify and isolate infected people or an effective antiviral that reduces the need for hospital beds. “That’s the nature of modeling: We put in what we know,” says Ira Longini, a modeler at the University of Florida. Nor do most models factor in the anguish of social distancing, or whether the public obeys orders to stay home. Recent data from Hong Kong and Singapore suggest extreme social distancing is hard to keep up, says Gabriel Leung, a modeler at the University of Hong Kong. Both cities are seeing an uptick in cases that he thinks stem at least in part from “response fatigue.” “We were the poster children because we started early. And we went quite heavy,” Leung says. Now, “It's 2 months already, and people are really getting very tired.” He thinks both cities may be on the brink of a “major sustained local outbreak”. Long lockdowns to slow a disease have catastrophic economic impacts and may devastate public health themselves. “It’s a three-way tussle,” Leung says, “between protecting health, protecting the economy, and protecting people’s well-being and emotional health.”
Based upon data we have been examining, albeit limited and a major defect of the Government's process, we know that models must reflect:
1. Demographics such as age, education, employment etc
2. Psychographics such as cultural propensity for proximity. Certain cultures have a great deal of physical contact such as hugging, kissing, large family dinners and the like.
3. Population density
4. Social interaction. Such things as where is food purchased, social gatherings such as religious sites
5. The transfer mechanisms. This is the ways the virus is initially transferred via proximity, surfaces, hand washing etc
6. Openness of the community. How open is the community to new entrants.
These are just a few. Then the model must be built by census tracts at the very least if not by zip codes. The NY Times model make the absurd assumption that the nation is homogeneous. Morgantown WV is NOT Bedford Sty!
If one is to build a model one must validate it. Or better, as Popper suggests invalidate it. One must build models and then with test data validate them, modify them.
In fact what engineers do is build models and then using the techniques of system identification adjust the model parameters and even its structure as data is obtained. There should be hundreds of Zip Code models and data adjusting each of them. From these dynamically adjusted models one then should attempt to determine why some regions are doing well while others are failing. That is the way decisions are made, not by one giant, one size fits all, model. This latter approach does a massive disservice and erodes trust. Lose that trust folks and we have real problems.
As to reigniting the country and the economy we can do so then with the models and DATA! However the facts are simple:
1. assuming no NEW infected people entering the pool, this burns out in 10-14 days after quasi quarantine.
2. assuming no mutations, the above remains true. However there is always the risk that this virus has a gain of function gene
3. assuming no Typhoid Mary types, namely infected but not sick and no antibody protection individuals, thus a silent carrier
Namely we really do not know the full scope of the pathology. Reinfects will occur, and that is why border control is critical. We quarantine horses, dogs and cats, a new Ellis Island? My concern is that there is a pandemic of politics and no one believes anyone else. That may be worse than the virus. So a suggestion:
1. Test test test
2. try it in a less critical set of locations. Kansas City or Richmond or Knoxville and test test and see what happens
Unwinding NYC is very unwise since I can almost assure people there are Typhoid Mary types somewhere. Bottom line: this will be a gigantic but necessary somewhat controlled experiment....and we must stop the politics, please.
One final thought. To understand the dynamics of this pandemic, perhaps one needs the expertise of market researchers not just epidemiologists. The human factor always dominates. Market researchers find out who, why and what people want to buy. It parallels disease progression. Really!
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