WHO - Confirmed cases doubled in 12 days

[JoeWras]

For the individuals with some symptoms, it is desirable to know if it is the virus or the regular flu. We need more tests for that.

I think they are getting that data.

At least in our county drive up facility, they first test for flu before testing for CV-19. Got the flu? No CV test for you.

 

[jollystomper]

For the individuals with some symptoms, it is desirable to know if it is the virus or the regular flu. We need more tests for that.

But for policy makers, all they need to know is the arrival rate at the hospitals. With the actual growth that they are seeing, they can see hospital beds, ICUs being filled a few weeks or months from now at that rate. And they know they need to put in drastic measures already.

There may be a lot more people with the disease and recovering well at home. That's fine, but you have to deal with the number of people needing hospitalization, and that's what you see right at your doorsteps. It may be only 1% or 10% of the total sick, but you do not have to deal with those lucky 99% or 90%.

It made it through my thick head a few days ago that this was probably the true reason for much of the concern - not some much virus itself or the virus death rate, but the strain the number of infected might put on the health system, impacting their ability not just to manage the virus but all other health issues as well.

 

[sengsational]

. COVID-19 is still in the noise level compared to seasonal flu.

Good point. I'd have to update my proxy recommendation to eliminate those cases (which could be done, because I think they have been testing for seasonal flu before 'wasting' a Covid-19 test kit).

 

[Freedom56]

Yes the number are going up as expected per this status:

https://www.worldometers.info/coronavirus/#countries


Infection rates rate in Europe will be higher than Asia as more people hug and kiss on the cheeks spreading the virus more readily whereas in Asia culturally they don't make physical contact when greeting someone.

 

[MichaelB]

Thanks. That graph will make larger countries look worse because they get to 100 cases faster; i.e., sooner in the spreading.

Seems the graph should be adjusting for population of each country if it is supposed to be comparing infection rates

I’m not sure about that. Initial growth, as depicted by the FT chart, might be independent of population size. After a certain level of penetration, then I would expect to see more cases in more populous territories. What the chart does not display is dispersion, and early growth might be much faster in dense areas. That would favor the US over a European country, as we are geographically much bigger and disperse.

Infection rates rate in Europe will be higher than Asia as more people hug and kiss on the cheeks spreading the virus more readily whereas in Asia culturally they don't make physical contact when greeting someone.

In the first WHO assessment on the Wuhan outbreak, the biggest single source of infection was family. Perhaps one of the drivers of the fast spread and accelerated rate of growth is young people living with parents.

 

[Freedom56]

In the first WHO assessment on the Wuhan outbreak, the biggest single source of infection was family. Perhaps one of the drivers of the fast spread and accelerated rate of growth is young people living with parents.

That could be as many younger people that are still with their parents and going out socializing are potentially bringing the virus back to their home.

 

[NW-Bound]

Seems the graph should be adjusting for population of each country if it is supposed to be comparing infection rates

To look at how the virus spreads, what the graph is showing is fine for a comparison.

Suppose you have two garden plots, one of 1 acre and the other of 10 acres.

Now if you take 100 seeds of weed and throw in the middle of each plot.

You then watch how many square feet of the plots are covered with weed at 1 week, 2 weeks, 1 month to see which plot is more fertile for the weed to grow.

The size of the plot does not affect how fast the weed grows at first. Not until the weed runs out of space to grow in the smaller plot. In the larger plot, it will continue to expand until the whole plot is covered.

 

[Chuckanut]

Here's one way of understanding what could happen if nothing is done.....

Suppose you have a 3 acre lake and 1 x 3 inch invasive lily pad species gets in. It reproduces daily (so 2X per day). The lake will be full of these lily pads in 48 days (and perhaps kills all the fish). How many days until the lake is half full of Lily Pads?
​

Do you know the answer?

Needless to say most people get this wrong. I suspect in this group, at least 1/2 will get it right.

To further explain the exponential growth and how it is all compressed into the last few days :

• At 40 days, the lake is only ~1/256th or 0.4% Lily pads barely visible. Although 40 days into the 48 day total timeline, there’s no clearly visible sign of an actual crisis.

Then the reality of doubling hits:
o 41: 1/128th of the lake is covered
o 42: 1/64th – probably now starting to be apparent
o 43: 1/32nd – obvious to all
o 44: 1/16th – Clearly a growing problem
o 45: 1/8th – Oh my gosh!
o 46: 1/4th – Where did that all come from?

 

[ERD50]

Here's one way of understanding what could happen if nothing is done.....

Needless to say most people get this wrong. I suspect in this group, at least 1/2 will get it right.

But these examples use an exponent of 2. I keep hearing "exponential growth", but I don't know what exponent they are using. Y = x^1.1 is also exponential, but it would look pretty linear.

Another difference from that illustration is that with CV, most people recover. So in that analogy, some of those lilies would stop covering the pond.

So I think it makes a difference if we are describing growth of total cases or deaths, or the growth of new cases or deaths,. All these terms seem to get thrown around interchangeably.

edit/add: You should have used 43 for the total days for the lake to be covered. Then everyone knows the answer (to everything )

-ERD50

 

[Go-NoGo]

Seems the graph should be adjusting for population of each country if it is supposed to be comparing infection rates

That is exactly right.
Note that for the purposes of this graph, FT chooses to track each European country separately. There is no line for the "EU"

 

[NW-Bound]

But these examples use an exponent of 2. I keep hearing "exponential growth", but I don't know what exponent they are using. Y = x^1.1 is also exponential, but it would look pretty linear.

The virus infection rate is spreading such that the number of total cases grow proportional to Y = k^X, where X is the number of elapsed days, and k is the ratio of day to day increase.

For Italy, k has been around 1.21 (21% daily increase), and for the last 4 days it has been lowered to 1.13 or 13% day-to-day.

Another difference from that illustration is that with CV, most people recover. So in that analogy, some of those lilies would stop covering the pond.

So I think it makes a difference if we are describing growth of total cases or deaths, or the growth of new cases or deaths,. All these terms seem to get thrown around interchangeably.

-ERD50

The number above is the accumulated total number of cases. This is what every published chart shows. Then, they also show the number of deaths, and recoveries. The rest is obviously people whose fate is still in the air. And that number is huge, compared to the dead and the recovered.

John Hopkins site shows 272,167 cases worldwide, with 11,299 deaths, and 87,403 recoveries. That's 173,465 still sick, or 64%.

How many of those 173,465 are hospitalized? How many should be hospitalized, but cannot be accommodated?

The number of sick people keeps increasing. At some point, all new cases cannot be accommodated. Death rate will blow up.

PS. Here is how the growth in the US looks like in the last 4 days. Perhaps some of that is caused by more testing, but 40%+ is very scary.

2020-03-17 5,656(+29%)
2020-03-18 ​​ 8,074(+43%)
2020-03-19 ​​11,980(+48%)
2020-03-20 17,235(+44%)

At an average rate of 45% from day to day, we will be doubling in less than 2 days. The number will grow 10x in 6.2 days, and 100x in 12.4 days.

Let's hope that the above increase was due to more testing.

 

[pb4uski]

I thought that this chart was interesting on showing why flattening of the curve to keep the infected within the capacity of the health care system is important.

 

[NW-Bound]

The above curves have been shown many times on this forum.

On the Web, they show the flat line according to the hospital limit a lot lower!

 

[ERD50]

....

PS. Here is how the growth in the US looks like in the last 4 days. Perhaps some of that is caused by more testing, but 40%+ is very scary.

2020-03-17 5,656(+29%)
2020-03-18 ​​ 8,074(+43%)
2020-03-19 ​​11,980(+48%)
2020-03-20 17,235(+44%)

At an average rate of 45% from day to day, we will be doubling in less than 2 days. The number will grow 10x in 6.2 days, and 100x in 12.4 days.

Let's hope that the above increase was due to more testing.

I'm very hesitant to put any weight on the new cases numbers, due to the variance in testing, as you mention.

But if I do a rough check of the daily deaths in USA, I get a similar number, doubling every 2 days. But we are on such a small part of the curve it's really stretching to project that out. We will see. But I will continue to focus on death rates, I think the testing rate is just too large of an influence on case numbers.

-ERD50

 

[NW-Bound]

The rate of increase in China was "doubling every 2 days" in late January until the entire Hubei province was locked down on Jan 29.

The rate of increase in Italy was "doubling every 3.6 days" until 4 days ago.

In both countries, the "days to double" were not lengthened until several days after lockdown was imposed. I think that was caused by "familial spreading", which lockdown and quarantine could not impact. It takes time for that to run its course.

With the family size in the US being smaller, I would expect to see the rate arrested sooner. When entire families either get sick or stay all clear or the sick hospitalized and separated from the rest of the family, that "familial spreading" stops.

Also, the number will not stop increase until after the incubation period.

 

[USGrant1962]

All this discussion of 2-, 3-, 6- day doubling points me back to the OP. Why is WHO suggesting that doubling in 12 days is somehow terribly worse than previous data when it is not? The exact quote from the WHO March 19 report is:

The number of confirmed cases worldwide has exceeded 200,000. It took over three months to reach the first 100,00 confirmed cases, and only 12 days to reach the next 100,000.

WHO certainly knows the logarithmic math of disease spread, so why would they suggest comparing two data points that are meaningless?

Fear mongering? Follow the money? What?

 

[NW-Bound]

The WHO number is worldwide, and includes the China number, which has stabilized at 81,279. And that reduces the growth rate.

Ex-China, the number has been doubling faster than over 12 days. I need to look up some numbers and do a bit of math to see what that is. Overall, I don't think it is as bad as in Italy, but cannot venture a number without doing some work. The ex-China number should be shorter than 12 days, but longer than 2 or 4 days.

Not an epidemiologist, but using common logic, I would surmise that the "days to double" vary between countries, depending on their family size, their customs, their habits, their mobility, how careful they are, etc...

I suppose that China's initial number was bad because it happened right before their New Year, and that's when people get together like we do at Thanksgiving. Wuhan is also a huge city and crowded with people.

In Italy, I think their convivial atmosphere and also tightly-knit families also hurt them. They first allowed restaurants when instituting the lockdown, but quickly banned that when finding out that while people in Milan were falling sick in droves, people down south in Rome were partying like nothing happened.

And observing what happened in Italy, Spain went straight to banning restaurants, because they already knew the quarantine would not work otherwise.

 

[NW-Bound]

OK, here we go.

I thought that I would need to look up the worldwide case number, then subtract out China's numbers to get the ex-China number. Then, I had to find historical data, to see when in the past that ex-China number was 1/2 of what it is now. There are many sites quoting the current statistics, but historical data seems to be well-hidden.

I finally found what I wanted at www.worldometers.info. I got the following info.

3/19/2020 - # of cases ex-China: 163,966
...
3/15/2020 - # of cases ex-China: 88,733
3/14/2020 - # of cases ex-China: 75,809

One-half of 163,966 is 81,983. Therefore, the time to double the confirmed cases ex-China is about 4.5 days.

Eventually, the growth may exceed the capability to test, particularly in 3rd world countries. This number may not be meaningful anymore.

 

[audreyh1]

Eventually, the growth will exceed the capability to test, particularly in 3rd world countries. This number may not be meaningful anymore.

Ha, ha - sorry

 

[NW-Bound]

^^^ Why so gleeful?

 

[Sunset]

Thanks. That graph will make larger countries look worse because they get to 100 cases faster; i.e., sooner in the spreading.

Actually the way I see the graph, USA with it's small population is worse than China because the USA graph is steeper and crosses the China graph soon. (Currently USA is nearly 20,000)

 

[Sunset]

It made it through my thick head a few days ago that this was probably the true reason for much of the concern - not some much virus itself or the virus death rate, but the strain the number of infected might put on the health system, impacting their ability not just to manage the virus but all other health issues as well.

Too bad officials won't tell it like it is:
Once the hospitals are packed full, in the rooms, ICU, in the hallways, in the stair landings.
When little Johnny goes out drinking and crashes his car, he will be left there to bleed out, as there is no sense sending an ambulance as the hospital is already over-filled.

 

[Sunset]

^^^ Why so gleeful?

Soon we will all be 3rd world countries

 

[NW-Bound]

For people who still think about infection spread rate vs the population size, I will explain again.

Remember again that the virus spread is not the same as the number of births in a country, which goes up when you have a higher population.

With the virus spread, the multiplication factor is not a function of the total population. One sick person infects 2 persons, who then infect 4 persons, and then 8, then 16, then 32, and 64, etc...

If another country is more infectious, then one sick person infects 3 persons, who then infect 9 persons, then 27, then 81, and 243, and 729, etc...

The country with the factor of 3 is going up a hugely steeper curve than the former country with a factor of 2.

 

[Sunset]

We have moved up to 5th spot, rapidly overtaking Germany by tomorrow and possibly Spain in confirmed cases.

At our rate of yesterdays increase of 5,594 confirmed cases, assuming only 20% need hospitalization, that is 1,119 beds !