Saturday, March 7, 2020

COVID -19, a Corona Virus



COD-19 is a corona virus, one of three types of common cold viruses. That’s it, a variant of the common cold, not something to strike fear into one’s heart. There are those who should be concerned: the elderly with heart, lung and/or kidney problems. Otherwise, it’s an inconvenience.

What stands out about this virus is that it is very contagious, and we are not yet certain if we know all possible means of transmission. We know that minuscule droplets expelled during coughing or sneezing can spread the disease. We know that on some surfaces the virus can remain a risk for up to four or more hours. We won’t know enough to make definitive statements for at least a year about how the virus spreads.

The disease is not particularly dangerous. It appears that many people, perhaps most people, who contract the disease will display no symptoms. Right now, with inadequate information, it appears that fatality rates will not exceed three percent of all who contract the disease, and may be as low as one percent, conceivably less. Influenza has a fatality rate of 0.1%, but is a concern because each year many tens of millions of people in the U.S. and across the world catch the flu.

My back-of-the-envelope math says the number of people with the virus will double every six months or more. Today, there are 100,000 cases diagnosed worldwide. By September 2020 that could be 200,000, and by March 2021 perhaps 400,000. At that rate there will be a million cases around the world in 2022, and a billion in 2025. That presumes that no effective vaccine can be developed in that time. Again, it’s my own back-of-the-envelope math, but I see an effective vaccine coming in 18-24 months. At that point it’s a logistics issue.

Some young, healthy people will die from the disease, but that always happens. We don’t know why, and those cases are outliers. If you’re under sixty and have no existing heart, lung or kidney conditions, you might be good for another sixty years.

3 comments:

  1. We gonna be on a million next week. That's official figures. Whats your comment on that?

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    1. Initial models for a novel virus are conservative, which is appropriate. They are regularly updated as new information is received, but, at least in the US, we are not seeing that. The old, very very wrong, numbers are still relied on. Were they correct there would be no reason to extend the lockdowns. They are not correct.

      Individual numbers are meaningless; case fatality rate and percentage of population infected are important. Hospitalization use rates cannot be compared between countries; South Africa has a lower threshold for hospitalization than Congo or Niger.

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  2. It is far more contagious than any corona virus I've seen, but it doesn't appear to be especially pernicious. It's a variant on the SARS virus, which was really bad. This one will probably be 10% hospitalization in the countries with low thresholds for hospitalization and a lot of hospital beds; 2.5% maybe ICU/intubation. I'm still predicting a 0.7% case fatality rate. It's doubling a lot quicker than I estimated, but all the models' predictions for hospitalization, intubation and death that can be checked against reality are far off in the US. The WHO model uses data from China (not transparent), Italy (admittedly overstated on hospitalizations, intubations and deaths) and Spain (incomplete, mostly from Catalonia and Madrid). The global champion so far is Taiwan.

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