The good news: You may have heard yesterday that Abbott Labs has been given FDA approval for a new test for COVID-19 virus. Better yet, the test is performed on a small desktop machine called the ID NOW platform. This piece of equipment is already in thousands of offices around the country and has been used for detecting influenza and RSV (respiratory syncytial virus). The system is simple and reliable. It uses the mucous from a sampling swab, mixed with appropriate reagents to look for the presence of very specific fragments of RNA from the virus. It can give a positive result in as little as a few minutes, or a negative result in about 15 minutes (the difference is that when there is a lot of virus you can see it quickly, but to go through a more thorough test takes a little longer).
Abbott Labs believes that this will allow for as much as 50,000 tests a day.
There are some complications including accessing sufficient chemicals (reagents) to complete the tests, but this is great news and will allow the healthcare community to begin to expand testing.
Other companies are expected to release similar types of tests in the next few weeks.
ALGEBRA
Sorry about having to take all of you back to high school math class, but I think it is interesting and informative and will help you make a little bit better sense of the numbers that we are being shown every day.
As of yesterday, March 27, these are the current numbers:
Total confirmed cases:
World: 622,157
US: 105,726
Total Deaths:
World: 28,799 % of Confirmed cases: 4.6%
US: 1,730 % of Confirmed cases: 1.6%
Now comes the first pieces of the, wait now…..Algebra.
Remember that a fraction has a top and a bottom number, the top number is called the “numerator”, in this case the number of deaths, and the bottom number is called the “denominator”, in this case the number of confirmed cases. So, when we calculate the “mortality” of the infection we divide the number of deaths by the number of cases confirmed.
We therefore see a rate somewhere between 1.6% and 4.6%.
As many talking heads have pointed out, the larger the denominator, the smaller this percentage becomes, so if there are actually a lot more cases out there that have not been confirmed, either because they have not presented themselves to the healthcare people, or have mild or asymptomatic infections, the actual number of cases may be much larger and therefore the mortality is actually much lower than the numbers we are seeing.
REALITY CHECK
Here is the problem, the two numbers that we are showing actually come from separate universes, and therefore are really not relatable to each other, or at least not in the simple way I described above.
So, what are the actual numbers that we can look at?
To understand what these numbers really reflect we need to build an, sorry again…EQUATION, and to make this equation we need to make some ASSUMPTIONS (best guesses). Here are the assumptions that we will use (I am using pretty conservative numbers based on the data that has been made public; one can suggest different numbers, lower or higher, but, as you will see, these numbers seem to be consistent with the numbers we are seeing:
Each person who is infected will infect 3 other people.
- 80% of infected people show mild or no symptoms
- The number of infections in a community doubles every 3 days.
- It takes at least 5 days after an individual is infected before they show the first symptoms
- It takes an additional 5 days before the individual is ill enough to present to a health system in a condition that warrants and allows for testing
- If the patient is hospitalized, and eventually dies, that process takes 15 days.
I think you can see that these assumptions are reasonably consistent with the reports we have seen, although some people may take up to 14 days to show symptoms, and some who unfortunately do not survive the disease pass away in a few days while others remain on respirators for over 20 days. The assumptions are made to try to find numbers that are conservative but based on what has been reported.
So now we can begin to build our equation.
Here is how we do it.
First, we look at a single individual who has just been infected. We call that Day0, the first day of infection.
Second, we look at the day that the individual begins to show the first signs of infection, in this case day 5. We call that DayFS.
Third, we look at the day that the individual begins to be severely ill so that they present for testing. We call that DayT.
Fourth, we look at the day that the individual dies. We call that DayD.
Based on the assumptions above, the span between Day0 and DayFS is about 5 days.
Based on the assumptions above, the span between Day0 and DayT is about 10 days
Based on the assumptions above, the span between Day0 and DayD is about 25 days.
Now we can go back and look at what is going on in the community. On Day0 there is one person infected. That person does not know they are infected and move about in the community. Not everyone they meet, interact with or touch will become infected, but over a period of time they will infect 3 other people. The rate at which they infect people is seen in the doubling rate, with is 3 days.
At Day0 there is 1 infection. 0 people have first signs
At Day3 there are 2 infections.
At Day6 there are 4 infections
At Day 9 there are 8 infections
At Day 12 there are 16 infections
At Day15 there are 32 infections
At Day18 there are 64 infections
At Day21 there are 128 infections
At Day24 there are 256 infections.