I was not going to write about COVID-19. However, our COUNTY IN UTAH has its first confirmed case, announced last night (6 March). This individual had been on a cruise ship several weeks ago. And was just tested for symptoms three days ago. Which means, obviously, they have been in contact (exposing) other people for several days. The infected person is age sixty.
I am sharing COVID-19 information with the intent to help, NOT panic. I am providing the website source information if you would like to learn more.
The following is a some information I extract from an article published by Our World in Data:
Incubation Period for the Virus:
While the mean incubation period is 5 to 6 days, the WHO adds that the incubation period can vary in a wide range of between 1 to 14 days.14
How long does COVID-19 last?
On average the disease lasts two weeks. The WHO reports that “the median time from onset to clinical recovery for mild cases is approximately 2 weeks.”15
Again this is based on the 55,924 confirmed cases in China
For severe and critical cases it is 3 to 6 weeks according to the same study.
And for those who eventually died, the time from symptom onset to death ranged from 2 to 8 weeks. This is important when interpreting the case fatality rate (see below). Measures of the CFR of an ongoing outbreak do (obviously) not include deaths of patients who will eventually die, but have not died yet at the time of measurement. This means that the current CFR would be lower than the eventual CFR.
What is Exponential Growth?
Exponential growth leads to large numbers fast, but most of us do not have a good intuitive grasp of this
As we said previously, the doubling time will change and it would be wrong to make projections based on a constant doubling time. But it is important to remind ourselves of the nature of exponential growth.
If during an outbreak the number of cases is in fact doubling, then the outbreak is spreading exponentially.
Under exponential growth 500 cases grow to more than 1 million cases after 11 doubling times.8 And after 10 more doubling times it would be 1 billion cases.
This is in no way a prediction for the number of cases we need to expect; it is simply a reminder that exponential growth leads to very large numbers very quickly even when starting from a low base