Posted on 03/24/2020 6:40:01 PM PDT by FreedomNotSafety
At present, it is tempting to estimate the case fatality rate by dividing the number of known deaths by the number of confirmed cases. The resulting number, however, does not represent the true case fatality rate and might be off by orders of magnitude [...]
A precise estimate of the case fatality rate is therefore impossible at present.
2019-Novel Coronavirus (2019-nCoV): estimating the case fatality rate – a word of caution - Battegay Manue et al., Swiss Med Wkly, February 7, 2020
The case fatality rate (CFR) represents the proportion of cases who eventually die from a disease.
Once an epidemic has ended, it is calculated with the formula: deaths / cases.
But while an epidemic is still ongoing, as it is the case with the current novel coronavirus outbreak, this formula is, at the very least, "naïve" and can be "misleading if, at the time of analysis, the outcome is unknown for a non negligible proportion of patients." [8]
(Methods for Estimating the Case Fatality Ratio for a Novel, Emerging Infectious Disease - Ghani et al, American Journal of Epidemiology)
In other words, current deaths belong to a total case figure of the past, not to the current case figure in which the outcome (recovery or death) of a proportion (the most recent cases) hasn't yet been determined.
EXACTLY!,
We have a bunch of data analysts working from home. They just make stuff up, and give it a name.
They count raindrops.
Let's do some math, shall we, with some REAL numbers, not estimates.
There are currently 30,418 active cases in NY STATE, not city. We'll use the percentages you provided from the city. 30,418 x 25% = ~7600 hospitalized cases in NY STATE. 44% of 7600 = ~3300 needing ventilators.
I hope you would agree that hospitalized patients who require ventilators would be considered in serious/critical condition, right?
Considering that there are currently only ~1400 cases that are categorized as serious/critical across the ENTIRE US, I'm not seeing those hyped up percentages as being realistic. Even if every single case needing a ventilator is in NY STATE, the actual number is less than half of the numbers reported by the state.
How to calculate the mortality rate during an outbreak
At present, it is tempting to estimate the case fatality rate by dividing the number of known deaths by the number of confirmed cases. The resulting number, however, does not represent the true case fatality rate and might be off by orders of magnitude [...]
A precise estimate of the case fatality rate is therefore impossible at present.
2019-Novel Coronavirus (2019-nCoV): estimating the case fatality rate – a word of caution - Battegay Manue et al., Swiss Med Wkly, February 7, 2020
The case fatality rate (CFR) represents the proportion of cases who eventually die from a disease.
Once an epidemic has ended, it is calculated with the formula: deaths / cases.
But while an epidemic is still ongoing, as it is the case with the current novel coronavirus outbreak, this formula is, at the very least, "naïve" and can be "misleading if, at the time of analysis, the outcome is unknown for a non negligible proportion of patients." [8]
(Methods for Estimating the Case Fatality Ratio for a Novel, Emerging Infectious Disease - Ghani et al, American Journal of Epidemiology)
In other words, current deaths belong to a total case figure of the past, not to the current case figure in which the outcome (recovery or death) of a proportion (the most recent cases) hasn't yet been determined.
Nice explanation of the “case fatality rate” but the big important number bet is the mortality rate based on deaths as a ratio of infections. Not cases.
So no spreading this around because it would cause people to focus on the really scary rate. The rate that has everyone convinced that they are gonna die if they get the WuFluVi
Exactly!
I was using the figures provided for the city last Friday, which undoubtedly at least a day old. But you’re right to check the math. Even WHO has put out clearly wrong numbers, such as using the fatalities/cases numbers as you rightly (and I have repeatedly) have demurred.
You really have no idea how many have had this strain of flu, no one does.
Thank goodness this strain is no where near the threat to the sub-population of children that this year’s regular flu has been.
Oh, and my comment was referencing the studies that show that hypertension, which is not usually much of a factor for the flu, appears to be a notable factor for this. So when it strikes down the “aged”, it is striking down a group which is substantially not redundant to the flu.
On March 6th the S. Korea death/cases rate was 0.6%. It’s continuing to creep up as people have time to die.
3/22 8897 104 2909 1.12%
3/23 8961 111 3166 1.24%
3/24 9037 120 3507 1.33%
3/25 9137 126 3730 1.38%
Projecting from this end, the current trajectory is a final number around 2.0-2.3% if no miracle cure, and no significant new cases.
This has been lauded as one of the most complete test surveys of the population.
///
If you’ve been watching the China numbers, and believe the China numbers, what you’ve seen is very few new cases in the past month now, and a continuing trickle of deaths at a rate that slowly increases the case rate - as the deaths are still coming at a slightly higher rate than the previous proportion compared to new cases.
Do you recall when the case rate for China was solidly below 2%?
I did not record the initial figures, so I only have them at hand since 3/5.
Date Cases dead recov dead/case
3/05 80422 3013 52229 3.746%
3/08 80735 3119 58588 3.863%
3/10 80956 3162 61559 3.905%
3/13 80945 3180 64194 3.928%
3/16 81032 3217 67910 3.970%
3/19 81155 3249 70535 4.003%
3/22 81409 3274 72808 4.021%
This has a trajectory to about 4.2-4.3% as a final rate if nothing changes. That will need to be offset by unknown cases, which looks to take it perhaps to about 3% or so...but it is China, so caveat emptor.
It was your argument on rounding that I was addressing.
The CDC does give a 0.1% as a typical mortality rate for a bad flu, but that is a generalization in association with different numbers.
Rounding and significant digits are whole things that come up from time to time. It surprises people to learn that at times 3.7 can be larger than 4 (because 4 is really somewhere between 3.5000 and 4.4999.
25% of what? 1,000,000? 100,000? 10,000? 1,000?
25% of confirmed cases of the Wuhan coronavirus in NYC before print time for last Friday (3/20).
25% of what? 1,000,000? 100,000? 10,000? 1,000?
Nice explanation of the “case fatality rate” but the big important number bet is the mortality rate based on deaths as a ratio of infections. Not cases.
There are currently 30,418 active cases in NY STATE, not city. We’ll use the percentages you provided from the city. 30,418 x 25% = ~7600 hospitalized cases in NY STATE. 44% of 7600 = ~3300 needing ventilators.
Working backwards, that is 17856*0.25*0.25*0.44=491. Completely reasonable at the time, even if the NYC paper is wrong, or the figure has changed (but that would need to be verified too).
That said, there *are* a lot of bogus numbers being thrown around, as well as outdated numbers, and we should be skeptical.
We can only go around this tree so many times. The CDC uses the .1% figure, which is rounded up using the traditional conventions. The alarmist crowd (including the WHO) used the estimated mortality rates for the Wuhan virus compared to the generic flu to frighten the entire world. We still don’t have sufficient data to make these projections.
True but only because cases are a small subset of infections.
Do you know how many cases there were last Friday?
Thanks for that. It should have been more obvious to me that you can’t account for it using a snapshot in time because there are too many cases with unknown outcomes.
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