Jump to content

Recommended Posts

Posted

Allright, I was having a beer an playing with numbers. I saw that somewhere in Israel they were actually doing group testing instead of individual ones. Basically they had 64 persons spit and then if the group was positive they would test 32, etc...

 

I tough it was an interesting concept, just like a DB works you can find a value much quicker by splitting the pile in halves over and over again.

 

I then went to take Quebec numbers (I live there). Assuming there is 0.3% of the population that has Covid, you don't want the group to be so large that 100% will test positive but you don't want the group so small that it's a waste of resources.

 

If I want about 25% of the initial test to turn out positive, how big should I make the initial group test? Well it turns out it's about 8000. For a population of 8M that is 1 000 tests (Quebec has a capacity of 12K/ test per day). So easily we can test all groups of 8000 on day 1, the next day, the groups that turned positive are split into 4 and so on.

 

Within 11 days we would have tested 8M people, found out the individuals, and we could repeat the process again. 22 days and we would be done with it. Quebec has a capacity of 12K tests per day, so that would not even interfere with the screening of the symptomatic persons.

 

Besides scaling 8000 persons per group what else am I missing here?

 

BeerBaron

 

I think the tests are not perfect and only pick it up if there's a certain amount? So 1/8000 people or whatever would be too diluted. Otherwise that's kind of genius. I am a chemistry & science layman so take it fwiw.

  • Replies 8.7k
  • Created
  • Last Reply

Top Posters In This Topic

Posted

Without schools being open, parents with kids are screwed.

 

How many of these parents take the summer off when their kids don't have school?

 

Not many take the entire summer of, but most do some vacation. Which won’t happen this year. Also most activities like summer camps /soccer won’t happen. Staying with friends/family/in-laws won’t happen.

 

My sons does now school via Zoom. I don’t think this works LT either, but this probably depends on the kid. He now need to organize himself to make sure he doesn’t miss any classes if none of us is at home, which sometimes fails. My wife usually works only half time as a Nurse but since this virus popped up in our area too, she works more hours than I do.

Posted

I was hoping Sweden would be the "control" here, so we would see what the effects of no lockdown could be.

 

But I don't see much material difference in Sweden's mobility versus Denmark or Norway. People everywhere are going out less. Yes there is some differences, but they all are minor when compared to Italy, where you can see an extreme drop in people going out.  As an effect of this, their economic numbers should also be pretty bad. Anyone from the region who can shed any light on the movement of people, shops and economic impacts in Sweden? Thanks in advance.

 

Sweden: https://www.gstatic.com/covid19/mobility/2020-04-11_SE_Mobility_Report_en.pdf

Other Nordic Countries:

https://www.gstatic.com/covid19/mobility/2020-04-11_DK_Mobility_Report_en.pdf

https://www.gstatic.com/covid19/mobility/2020-04-11_NO_Mobility_Report_en.pdf

 

Italy:

https://www.gstatic.com/covid19/mobility/2020-04-11_IT_Mobility_Report_en.pdf

 

 

Posted

Lol. Please point to me where I was wrong Dick?

 

Sure.  It's pretty simple.  You were saying early on that hundreds of thousands or millions of people in the USA probably had it, and that testing was pointless.  Then, hundreds of thousands of people in NYC actually got it and more than 10K died, which wouldn't have happened if all those people were infected already. And the countries that have done the best have been the ones who were good at testing and tracing.

 

That said, I have come down more harshly on you than others simply because you're dishonest, and because--if you are actually a doctor--I think that dishonesty makes you dangerous. (I would have no problem whatsoever with you if you were simply wrong and adjusted your beliefs as the evidence changed. In fact, I'd have a whole pile of respect for you, if that were the case.)

 

I also think that anyone who makes the argument that the worst case didn't arise so the worst case scenario couldn't possibly be true--after there was a massive, month-long lockdown to prevent the worse case scenario--is either disingenuous or stupid or both.

 

Can you please show data to prove that?

 

I am looking at worldometer

 

Country      Deaths/1M population    Tests/1M population

Spain                  402                          13,908

Italy                    358                          18,481

France                263                            5,114

UK                      190                            5,876

Switzerland        143                          22,993

USA                      86                            9,845         

 

As I went down the Deaths/1 Million population of some larger western countries, I faily to see a clear trend with relation to Tests rate.

 

             

Posted

And the countries that have done the best have been the ones who were good at testing and tracing.

 

Can you please show data to prove that?

 

I was mainly talking about Taiwan, Germany, and South Korea. (Full disclosure: a couple of weeks ago, Singapore would've been on my list of test & trace success stories, but it seems to be breaking down.)

 

Country      Deaths/1M population    Tests/1M population

Spain                  402                          13,908

Italy                    358                          18,481

France                263                            5,114

UK                      190                            5,876

Switzerland        143                          22,993

USA                      86                            9,845     

Germany              45                          20,629

S.Korea                  9                          10,509

Japan                    1                                745

Taiwan                    0.3                          2,129

 

 

Still no trend.  Taiwan doesnt follow.  Taiwan has one of the lowest testing rates and lowest death rates. 

Next is Japan with lowest testing rates in list above and deaths only above Taiwan.

Richard, please do check my data on Worldometer.

 

It is very difficult to rely on testing when vast majority of infected have no symptoms. 

You have to test most of 340 million in US. Thats not an easy job.

The highest in the list above is Switzerland which tested 2.3% of its population.

Posted

I found this interesting: Dutch bloodbank reports in preliminary discussion antibodies found in ~ 3% of 4208 blood donors they have tested. All blood donors should be symptom free and not have had contacts with anyone with symptoms for 14 days before they are allowed to donate. I'm sure you could argue the people who donate blood by definition are not a perfect representation of a population, but otherwise this seems pretty random to me (and probably underreporting as everyone tested is by definition asymptomatic).

 

Netherlands has a 17 million population, with right now 28K registered cases and 3100 deaths.  3% of 17 million is 500K.  So suggests real number of infected patients compared to patients tested positive could be 18x as large. 3100 deaths is surely underreported as it is everywhere (nursing home deaths etc), but let's make it 5000-10000, you get a mortality rate of 0.1%-0.2%.

 

So, based on this report, herd immunity seems far away, except maybe in regions that have been hit particularly hard.  On the other hand, death rate does seem much, much lower than initial stats (and some people) were saying . And number of asymptomatic patients are many times the number of patients that get sick (as more and more research is now suggesting).

 

Posted

I'm trying to ask this uncontroversially mostly medical professionals here: assuming a gradual relaxation of the lockdown with no vaccine, no treatment, and no (or minimal) testing/tracking. Would you say going out is acceptable or too risky? Let's assume a medium-high risk state like MA. Let's assume not super vulnerable person.

If we want to talk concrete "going out" categories, let's say going to parks, general shopping, meeting friends/family, going to office/work, going to a restaurant (I tried to order this from least risk to most risk).

Outcome of "severe" infection sounds very scary. That has to be balanced with infection risks though.

I know this is a bit theoretical and uncertain, but since there's a talk of "relaxation" even in NY state, maybe this could be useful.

I could open a new topic... but probably not worth it.

Thanks

Complement to Cobafdek, in the middle of the (tribal) fight.

Your question is difficult to answer (it feels like: What's the risk of shorting Tesla stock?) and it includes the evaluation of tail risk.

Since my background has some relevance and since i need to address this question now, here's a tentative answer.

 

It seems that the opening will be gradual and the rate of opening will be inversely proportional to virus resurgence. So you'll need to adjust your risk management for your area and with the evolving picture. I work with a scenario of localized and limited resurgence activity during the opening with no second or third wave although this could become low-grade seasonal. I'd say testing will be useful for certain areas of concern but it's hard to see how testing at large will be useful for local decisions. I would also add that herd immunity is not a black or white concept. Relative herd immunity may be much lower than the often 60-70% quoted.

 

1st risk: risk that you become a spreader without being sick

This is a population-level risk but also an individual risk as you may bring the disease to loved ones who may be susceptible (known risk factors or even rarely idiosyncratic).

Then, your cumulative (i share DocSnowball's realism about molecules and timeline) individual risk is likely lowish (and will evolve over a fairly long time), especially if you take basic precautions (basic distance, washing hands, and avoiding social contacts with older (or frail) friends or family members). The concept of position sizing (extent of your social participation along the activity risk spectrum you describe) could be applied as a degree of conviction that your area is safe (from publicly announced statistics, hospital activity level etc).

 

2nd risk: risk that you become significantly sick

Apart from idiosyncratic risk, which is very low, your risk will be proportional to risk factors (age, lung disease, obesity, diabetes etc) with individual risk factors being likely more than additive and serious event risk going up exponentially with the overall level of frailty. Assuming not super vulnerable means no major risk factors, it seems that your risk of becoming significantly sick is very low (do your own work  :) ).

 

What you do as an individual is also tied to your risk personality. If you used to go for the flu vaccine every year versus not even worrying about becoming sick will have an influence on future behavior vs CV. It's possible CV becomes old news very rapidly especially if other events take eyeballs off the bug (and its consequences).

 

@Jurgis: personally I wait for one incubation period to start to trust the data - cases in your state have gone down and stayed down for 14 days; and for two incubation periods for giving the all clear - cases are in single digits or zero in your state for 28 days. Try to phase your return back towards activities in that way. The most essential activities come first, and the lowest risk will be where you're not within 3-6 feet of others and are outdoors. The highest risk will be going to healthcare facilities and crowded indoor gatherings. One thing I've learned is this virus is 2 SD beyond what I've expected of it in spreading, so better to be safe than sorry. The fact that it spreads so easily in healthcare facilities (10k healthcare workers infected in the US!!! cities with public transport really hit hard) tells me there is effective transmission beyond droplets, perhaps it lives well on surfaces + asymptomatic/presymptomatic people spread it early on...(you fill in your thoughts)

 

Maybe a smart idea to build a checklist of do's and don't to follow before, during and after going out and test-drive/refine it when you start going out. I'll try to get it started.

 

Is this activity essential?

What is the risk in this activity? How can it be substituted or minimized?

Hand sanitizer - check. Wipes - check. Mask - check.

Keeping social distance, minimizing touches, minimizing time spent/risk incurred in the activity

Sanitize when done, dispose mask and take footwear off safely on return

Hand washing when home

Dispose clothes for washing later, hand washing again

Posted

FWIW my prediction is that we'll try to do it the right way (tracking, testing etc), fail miserably, and then the destruction will be so great we'll just go "Fuck it" and go back to work anyway and tell grandma to stay home and order groceries online.

Posted

I found this interesting: Dutch bloodbank reports in preliminary discussion antibodies found in ~ 3% of 4208 blood donors they have tested. All blood donors should be symptom free and not have had contacts with anyone with symptoms for 14 days before they are allowed to donate. I'm sure you could argue the people who donate blood by definition are not a perfect representation of a population, but otherwise this seems pretty random to me (and probably underreporting as everyone tested is by definition asymptomatic).

 

Netherlands has a 17 million population, with right now 28K registered cases and 3100 deaths.  3% of 17 million is 500K.  So suggests real number of infected patients compared to patients tested positive could be 18x as large. 3100 deaths is surely underreported as it is everywhere (nursing home deaths etc), but let's make it 5000-10000, you get a mortality rate of 0.1%-0.2%.

 

So, based on this report, herd immunity seems far away, except maybe in regions that have been hit particularly hard.  On the other hand, death rate does seem much, much lower than initial stats (and some people) were saying . And number of asymptomatic patients are many times the number of patients that get sick (as more and more research is now suggesting).

This is interesting. Netherlands used policies more or less intermediate compared to places like Austria on one side and Italy on the other with, as expected, more or less intermediate results. Netherlands has also produced interesting work on influenza vaccine effectiveness and is a good relative European student in terms of historical flu vaccinate rates.

It looks like (picture developing) that the CV does behave (intrinsic features) similarly to the influenza virus, with the main difference being that the population tends to have a much lower natural immunity to it and there is no vaccine, not even a partially effective one. Reasonable extrapolation of data in the Netherlands suggests that the eventual death rate from CV (with some social distancing and other basic measures) will look like (compare to a reasonable degree) the typical death rate for influenza, had there been a 0% rate of vaccination.

What society is doing is basically trying to adapt (with various levels of 'success') to this new and evolving reality.

 

@LC

Thank you for supplying the link for the European monitoring of mortality with seasonal variations.

Posted

I found this interesting: Dutch bloodbank reports in preliminary discussion antibodies found in ~ 3% of 4208 blood donors they have tested. All blood donors should be symptom free and not have had contacts with anyone with symptoms for 14 days before they are allowed to donate. I'm sure you could argue the people who donate blood by definition are not a perfect representation of a population, but otherwise this seems pretty random to me (and probably underreporting as everyone tested is by definition asymptomatic).

 

Netherlands has a 17 million population, with right now 28K registered cases and 3100 deaths.  3% of 17 million is 500K.  So suggests real number of infected patients compared to patients tested positive could be 18x as large. 3100 deaths is surely underreported as it is everywhere (nursing home deaths etc), but let's make it 5000-10000, you get a mortality rate of 0.1%-0.2%.

 

So, based on this report, herd immunity seems far away, except maybe in regions that have been hit particularly hard.  On the other hand, death rate does seem much, much lower than initial stats (and some people) were saying . And number of asymptomatic patients are many times the number of patients that get sick (as more and more research is now suggesting).

This is interesting. Netherlands used policies more or less intermediate compared to places like Austria on one side and Italy on the other with, as expected, more or less intermediate results. Netherlands has also produced interesting work on influenza vaccine effectiveness and is a good relative European student in terms of historical flu vaccinate rates.

It looks like (picture developing) that the CV does behave (intrinsic features) similarly to the influenza virus, with the main difference being that the population tends to have a much lower natural immunity to it and there is no vaccine, not even a partially effective one. Reasonable extrapolation of data in the Netherlands suggests that the eventual death rate from CV (with some social distancing and other basic measures) will look like (compare to a reasonable degree) the typical death rate for influenza, had there been a 0% rate of vaccination.

What society is doing is basically trying to adapt (with various levels of 'success') to this new and evolving reality.

 

@LC

Thank you for supplying the link for the European monitoring of mortality with seasonal variations.

 

Apologies. To my own embarassment upon re-reading this I made a primary school calculation error here (my only defence: it was early).  3100 out of 500 000 obviously isn't 0.06%, but 0.6%, which makes quite a bit of difference here, Still not quite the 3% some are saying, but definitely not flu percentages either.

Posted

https://www.marketwatch.com/story/wheels-are-in-motion-for-widespread-coronavirus-antibody-testing-in-new-york-2020-04-15?mod=mw_latestnews

 

Antibody testing will be key to getting economies around the country moving again.

 

“We have these estimates that it could be millions of people” in the U.S. who will qualify to go back to work once an antibody test is deployed, said Joshua M. Epstein, a professor of epidemiology at the New York University School of Global Public Health.

 

"Until the tests are available, there’s no way of knowing just how many New Yorkers have had the virus, Racaniello said. He estimates it could be 10 times more than the official tally, due to lack of early testing and the potentially large number of asymptomatic carriers. "

 

And no one hit me with that its been spreading since you said millions of people 5-6 weeks ago so thats why I could be that high now. If Dalal can say the curve was flattened and disaster was averted because of the lock down, then you cant in same breath said it has been spreading rapidly. Cant have it both ways.

Dear orthopa, not taking sides, but Exponencial growth makes it possible. numbers were growing over 30% a day in most places prior to lockdown, which means healthcare capacity would be overwhelmed in those places were it not for the lockdowns: lockdowns earn you time by reducing  case growth from over 30 to sub 10% (over here after a few weeks we are now on a 3-4% case growth per day). with that time you can plan, prioritize, buy supplies, organize campaign hospitals, etc. at over 30 % a day (in some places maybe over 50% a day) everybody gets sick before you can do anything.

However, millions of cases is not something strange in a country as big as the us. And with a double in less than 3 days you very quickly reach the millions. The lockdowns however might have turned many millions into a few millions, which means this thing will last longer, but should not kill so many

 

I agree, and believe probably millions. Spreading rapidly and what that means is highly up for debate and probably useless to discuss right. Throw a number and situation out there and it seems plausible.

 

My point was if the lock down slowed the spread and people stayed in their house, wore masks etc then the growth should have slowed exponentially. NY has been on a "pause" for a month. New cases caused by community spread should have hit rock bottom and in reality only now be from spread within families/close contacts etc. Once the pre lockdown infections progressed to recovered or death where else would the infection be coming from? So if NY is at 2 million cases after a complete lock down taking into account the slowest possible spread from the most extreme measures contemplated, that number of infected now is coming from a higher then expected initial base before the lock down.

 

Whether or the lock downs actually worked or not maybe up for debate around the country. Different states locked down at different times. Different restrictions in each state. Some have only essential services, some don't. All seem to be working. Its likely the social distancing, standard precautions, hand washing, masks, etc that is having the most effect since that is probably the most consistent measure practiced across the entire US.

There is, by definition, a delay between infection and diagnosis, which would be about 10-14 days in an unadvised population. In adition, taking into account new york crowding, subways, etc, instead of the 2-3 days duplication rate seen in most countries (which include scattered populations), it is highly likely duplication rate was higher than once a day (or over 100% daily growth rate, just think how many people a subway user infects in just a day, and then imagine how many people those infected subway users infect). That would conservatively mean infected people in NYC would be 2^10 higher (or 1024x higher) than known by the time they implemented the lockdown, and that does not include prior cases (which were certainly present, but nor necessarily by that much) not diagnosed by various motives. If you take into account that base, millions will not be that far away, even if the lockdowns slowed everything to 5% a day immediately (which is doubtful: close contacts from yet not contagious people would still have to be infected, so you can count on at least 1-2 weeks more of a reasonably higher growth rate).

Posted

I found this interesting: Dutch bloodbank reports in preliminary discussion antibodies found in ~ 3% of 4208 blood donors they have tested. All blood donors should be symptom free and not have had contacts with anyone with symptoms for 14 days before they are allowed to donate. I'm sure you could argue the people who donate blood by definition are not a perfect representation of a population, but otherwise this seems pretty random to me (and probably underreporting as everyone tested is by definition asymptomatic).

 

Netherlands has a 17 million population, with right now 28K registered cases and 3100 deaths.  3% of 17 million is 500K.  So suggests real number of infected patients compared to patients tested positive could be 18x as large. 3100 deaths is surely underreported as it is everywhere (nursing home deaths etc), but let's make it 5000-10000, you get a mortality rate of 0.1%-0.2%.

 

So, based on this report, herd immunity seems far away, except maybe in regions that have been hit particularly hard.  On the other hand, death rate does seem much, much lower than initial stats (and some people) were saying . And number of asymptomatic patients are many times the number of patients that get sick (as more and more research is now suggesting).

This is interesting. Netherlands used policies more or less intermediate compared to places like Austria on one side and Italy on the other with, as expected, more or less intermediate results. Netherlands has also produced interesting work on influenza vaccine effectiveness and is a good relative European student in terms of historical flu vaccinate rates.

It looks like (picture developing) that the CV does behave (intrinsic features) similarly to the influenza virus, with the main difference being that the population tends to have a much lower natural immunity to it and there is no vaccine, not even a partially effective one. Reasonable extrapolation of data in the Netherlands suggests that the eventual death rate from CV (with some social distancing and other basic measures) will look like (compare to a reasonable degree) the typical death rate for influenza, had there been a 0% rate of vaccination.

What society is doing is basically trying to adapt (with various levels of 'success') to this new and evolving reality.

 

@LC

Thank you for supplying the link for the European monitoring of mortality with seasonal variations.

 

Apologies. To my own embarassment upon re-reading this I made a primary school calculation error here (my only defence: it was early).  3100 out of 500 000 obviously isn't 0.06%, but 0.6%, which makes quite a bit of difference here, Still not quite the 3% some are saying, but definitely not flu percentages either.

 

https://www.thelancet.com/action/showPdf?pii=S1473-3099%2820%2930243-7

 

See Table 1. Estimated CFR 1.38%, >10x deadlier than the Flu. The best CFR from published studies is in the vicinity of 1% which is 10x deadlier than Flu.

 

The 3% antibodies is not good news for feasibility of herd immunity as you note. British government backed off of that strategy quickly...

Posted

 

In my 53 years of seeing dumb things, defunding the WHO in the middle of a global pandemic is the winner.

 

Sure, on the surface it sounds like it, but removing political biases on the part of those trumpeting this "horrible decision", is it not credible to at least question these people?

 

They've been horribly wrong about things directly related to the purpose of their existence and continuously seem to have a pro China position, even down to the OK being given to re-open wet markets...

Posted

is it not credible to at least question these people?

 

There's definitely a time and place for questioning (and even for fund cutting if need be), I totally agree; But surely we can also all agree that time is not now.

Guest cherzeca
Posted

I found this interesting: Dutch bloodbank reports in preliminary discussion antibodies found in ~ 3% of 4208 blood donors they have tested. All blood donors should be symptom free and not have had contacts with anyone with symptoms for 14 days before they are allowed to donate. I'm sure you could argue the people who donate blood by definition are not a perfect representation of a population, but otherwise this seems pretty random to me (and probably underreporting as everyone tested is by definition asymptomatic).

 

Netherlands has a 17 million population, with right now 28K registered cases and 3100 deaths.  3% of 17 million is 500K.  So suggests real number of infected patients compared to patients tested positive could be 18x as large. 3100 deaths is surely underreported as it is everywhere (nursing home deaths etc), but let's make it 5000-10000, you get a mortality rate of 0.1%-0.2%.

 

So, based on this report, herd immunity seems far away, except maybe in regions that have been hit particularly hard.  On the other hand, death rate does seem much, much lower than initial stats (and some people) were saying . And number of asymptomatic patients are many times the number of patients that get sick (as more and more research is now suggesting).

This is interesting. Netherlands used policies more or less intermediate compared to places like Austria on one side and Italy on the other with, as expected, more or less intermediate results. Netherlands has also produced interesting work on influenza vaccine effectiveness and is a good relative European student in terms of historical flu vaccinate rates.

It looks like (picture developing) that the CV does behave (intrinsic features) similarly to the influenza virus, with the main difference being that the population tends to have a much lower natural immunity to it and there is no vaccine, not even a partially effective one. Reasonable extrapolation of data in the Netherlands suggests that the eventual death rate from CV (with some social distancing and other basic measures) will look like (compare to a reasonable degree) the typical death rate for influenza, had there been a 0% rate of vaccination.

What society is doing is basically trying to adapt (with various levels of 'success') to this new and evolving reality.

 

@LC

Thank you for supplying the link for the European monitoring of mortality with seasonal variations.

 

Apologies. To my own embarassment upon re-reading this I made a primary school calculation error here (my only defence: it was early).  3100 out of 500 000 obviously isn't 0.06%, but 0.6%, which makes quite a bit of difference here, Still not quite the 3% some are saying, but definitely not flu percentages either.

 

https://www.thelancet.com/action/showPdf?pii=S1473-3099%2820%2930243-7

 

See Table 1. Estimated CFR 1.38%, >10x deadlier than the Flu. The best CFR from published studies is in the vicinity of 1% which is 10x deadlier than Flu.

 

The 3% antibodies is not good news for feasibility of herd immunity as you note. British government backed off of that strategy quickly...

 

"However, after further adjusting for demography and under-ascertainment..."

 

what does this mean?  oh, that the so-called scientists fudged their data to get the results they wanted, is what this means.  garbage in, garbage out.  good enough for Dalal though.

Posted

"However, after further adjusting for demography and under-ascertainment..."

 

what does this mean?  oh, that the so-called scientists fudged their data to get the results they wanted, is what this means.  garbage in, garbage out.  good enough for Dalal though.

 

You're right, this Lancet study is good enough for me for the time being. And so are you! You treasure, you!

Guest cherzeca
Posted

"However, after further adjusting for demography and under-ascertainment..."

 

what does this mean?  oh, that the so-called scientists fudged their data to get the results they wanted, is what this means.  garbage in, garbage out.  good enough for Dalal though.

 

You're right, this Lancet study is good enough for me for the time being. And so are you! You treasure, you!

 

first figure out how to spell my user name dipstick.  then I will engage you, though I will likely debase myself in the process.

Guest
This topic is now closed to further replies.



×
×
  • Create New...