wuhan - coronavirus

[Ausmumof3]

https://www.medrxiv.org/content/10.1101/2020.08.11.20171843v2.full.pdf+html
 

I think this is good news on B and T cells.  Don’t have time and mental energy to read right through it right now 

[TCB]

Any word on the outbreak in New Zealand? Have they been able to confirm the source? I’ve started wiping down my frozen stuff again but would like to stop if it’s not necessary lol!

[Ausmumof3]

9 minutes ago, TCB said:

Any word on the outbreak in New Zealand? Have they been able to confirm the source? I’ve started wiping down my frozen stuff again but would like to stop if it’s not necessary lol!

Last I saw they don’t believe it was the frozen foods because they swabbed and found only low level surface contamination which they deemed most likely to have come from the infected worker handling it. However that was yesterday and at that point they still hadn’t tracked the source so it’s hard to be absolutely certain I think. 

[Pen]

2 hours ago, Plum said:

sorry if this has been mentioned. 

Osterholm has some things to say about the media calling on so-called experts that may be experts in their field but not epidemiologists and how that is creating message chaos and confusion. Around the 50 minute mark he discusses the different  tests and goes into the real world problems with dipstick tests. To start, its self-selecting and young people would use it to after risky behavior, confirming to themselves that their risky behavior is not risky at all. 

https://youtu.be/upzHueYqZDA

 

 

Agh.  😡

Note: I only got part way through the long interview and may change this later, but I am commenting mainly on your own summary above particularly the bold part. And listening to that area of what he said. 

I  agree that there is major message confusion.  And Osterholm himself is part of that imo.

Take masks for example.

I know Fauci first came out against them and then later did a 180.

 

My recollection is that Osterholm didn’t do a complete 180, but he was fairly negative or at least not positive about masks on a quite similar basis to what you wrote above about dipsticks.  Masks, as I understood what he had conveyed (which could be wrong but if wrong means he himself may not be as clear in his messaging as he may think) would give a false sense of security, while at best they would only make it safe to do something like ride in a car with someone (positive) for 20 minutes instead of 10 minutes. 

That’s not necessarily incorrect. But it  (the false sense of security argument) is being used by people of good will and reasonable intelligence as a reason not to mask.   

So then as Masks were learned to probably help quite a lot, maybe around late July,  Osterholm came out and says he didn’t tell people not to mask. No. In anything I heard He did not directly say don’t mask.  But he said things that clearly gave that impression, that masks could give false sense of security and thus conveyed a sense of negativity toward masks. .   And he had a tone about it that made it sound to me like he thought it would be akin to thinking a layer of bubble wrap would help to protect from a fall off a tall building.  A “wear a mask if you want, but don’t expect it to help any” tone. 

 

So far as I can tell, young adults who believe their risky behavior is not risky, or who deliberately embrace risk are already doing that. Would dipstick tests increase that? Idk. But there are a lot of people in many many circumstances who won’t use such tests to justify high risk behavior and for whom it might, like masks, be another potentially extremely helpful tool to have.  

 

I think there are huge numbers of responsible people who could make good use of it by testing every few days even if completely Asymptomatic in terms of helping to decide even whether to go in to work or whether to send children to school and that it could be a huge help. I don’t think MO is correct that the world is divided between ultra-risky behavior young adults and people in tiny bubbles and who can stay that way indefinitely as the only ones who would use such tests. 

 

ETA And his argument that sounds like he thinks it would be especially bad for low income and so on and African Americans he mentioned specifically to be able to know whether they are positive because they cannot isolate is especially bizarre and or egregious sounding to me.  I think his hypothetical single mother might want to keep distance from her own children as much as she could for 14 days if she knew she were positive, and that we as a society might want to use other resources to help such a family to confirm the positive and to be able to isolate for days most likely to spread infection—not to prefer making it hard to know that there’s a positive so that they carry on as usual.  (Around 52 minutes point.)   I can certainly say for myself as a single parent with somewhat reduced resources that I would certainly want to know if my child or myself were positive and to do what could be done not to spread infection to each other (or at least lower the viral load—better no hugs for 2 weeks than both people really sick) and to do what one could to not spread infection to others.  Even if someone has to keep working, I don’t see how not knowing helps, other than  an “ignorance is bliss” type argument. 

 

Imo, approve the home dipstick type tests Give them a nice big black box warning that a negative result does not mean definitely negative. So don’t go do risky things based on a negative result. False negatives already exist for the current tests, which in many places are still very hard to access, and slow to get results for.  

And for some people even if testing does not have major hoops there are problems like living in a rural area 3 hours drive or more from nearest test location. Should one drive oneself if feeling ill? Should someone else drive the ill person using masks that only give 20 minutes in car protection?  

 

Is Osterholm leaving epidemiology and moving into psychology ?  What is his expertise in psychology?

 

even if he is strictly in his own area of expertise, Experts can make major errors.  

For a non current example,  Benjamin Rush (I think it was from books on viruses I have been reading) told people that yellow fever was caused by foul air and told people to flee yellow fever areas — thus spreading infectious disease far and wide.

 

Edited August 21, 2020 by Pen

[Pen]

4 minutes ago, Plum said:

I thought you’d have some things to say about what he said. 
 

I do appreciate different perspectives on this. 

 

I am still steamed about the Osterholm talk, or at least the part around 50 min in I listened to.  

I want to keep thinking experts make “errors”. 

But Dr Zelenko used the term “genocide.”

and listening to the part about how it would be better for a single, maybe person of color, mom to not know...     I am thinking no. This is not mere error. Zelenko is right.  

[Pen]

1 hour ago, Plum said:

I'll have to listen to that part again. That is extreme. I have heard that line of thought before, specifically regarding people in small NY apartments needing to self-isolate. Our first apartment was a studio; expecting us to be able to self-isolate in that apt would have been impossible. I was thinking about those TB homes and even leper colonies (yeah I know) where we made a place for people to go to be cared for while they were sick and contagious. There doesn't seem to be enough options for families that live in small spaces to be able to protect one another. AFAIK, HCW got the free hotel rooms, not the cleaning crew. 

You should write to him. He answers questions all the time. Maybe he'll elaborate more on what he means. 

 

Yeah, maybe I’ll write to him. I’ve been writing to local school board currently where I think I have more potential impact. I probably should listen to the whole Cidrap youtube  to not possibly be misunderstanding the context first. 

——

 

I’ve lived in NYC studio too. Not being able to self isolate might still allow some ability to try to reduce viral load.  Open windows, use what one could use, including perhaps masks. Even sleep with heads facing away instead of same direction...  or perhaps for shared housing situations even curtaining an area with sheets might be possible to reduce viral load. 

My current living location isn’t great for isolating either since it’s a compact house with only one bathroom. But IMO it would be useful to know and to use major diligence following a positive test, a level of precaution which really cannot be maintained minute by minute for months, but certainly could be for a couple of weeks.

 I know in your family no one but your husband got sick even without particular precautions, but that is not guaranteed. 

 

 

[Ausmumof3]

9 cases in qld today.  6 are linked to the detention centre (6 positive and 56 negative so far - they are testing close to 600 people) and unfortunately several in people who work across multiple locations including one in. disability accommodation services.  3 cases in offshore cargo ships.

This is pretty seriously concerning.  Gatherings in homes and outdoors have been limited to 10 across Brisbane.  The rest of QLD have limits of 30 now.  Venues with covid safe plans can continue to operate at this stage as normal.

ABC: “Chief Health Officer Jeannette Young said there was a significant chance more cases would be detected over the coming days.

She said it was essential people got tested if they were feeling unwell.

"Everyone should think about their personal COVID-safe plan, and if they're in that vulnerable group, start thinking about how they can manage themselves," she said. 

"We'll get through this together, I'm very confident we will, if everybody listens to the messaging and we all play our part to keep everyone safe.

"The key is social distancing. 

"This weekend if you are going to a shopping centre and there is no social distancing, you should leave immediately."

[Ausmumof3]

6 hours ago, Plum said:

I'll have to listen to that part again. That is extreme. I have heard that line of thought before, specifically regarding people in small NY apartments needing to self-isolate. Our first apartment was a studio; expecting us to be able to self-isolate in that apt would have been impossible. I was thinking about those TB homes and even leper colonies (yeah I know) where we made a place for people to go to be cared for while they were sick and contagious. There doesn't seem to be enough options for families that live in small spaces to be able to protect one another. AFAIK, HCW got the free hotel rooms, not the cleaning crew. 

You should write to him. He answers questions all the time. Maybe he'll elaborate more on what he means. 

Here in my state any positive cases in a house with one bathroom get moved to medi hotels.  Obviously that’s only viable with low numbers though.

[TarynB]

9 hours ago, Pen said:

 

I am still steamed about the Osterholm talk, or at least the part around 50 min in I listened to.  

I want to keep thinking experts make “errors”. 

But Dr Zelenko used the term “genocide.”

and listening to the part about how it would be better for a single, maybe person of color, mom to not know...     I am thinking no. This is not mere error. Zelenko is right.  

Yeah, you should listen to the whole thing. Dr. Osterholm's point was that the virus is now so widespread in the US that we can't test (and contact trace) ourselves out of the pandemic. Because so many people aren't willing to change their behavior. And that all the arguing in the media about how many tests are available and all the different types of tests and which tests are accurate vs inaccurate is all a big waste of time. We and the media should be focusing instead on getting people to understand that changing their behavior is the key to controlling the spread. Testing alone won't get us there.

[Ausmumof3]

800,000 deaths on worldometer now.

[Pen]

1 hour ago, TarynB said:

Yeah, you should listen to the whole thing. Dr. Osterholm's point was that the virus is now so widespread in the US that we can't test (and contact trace) ourselves out of the pandemic. Because so many people aren't willing to change their behavior. And that all the arguing in the media about how many tests are available and all the different types of tests and which tests are accurate vs inaccurate is all a big waste of time. We and the media should be focusing instead on getting people to understand that changing their behavior is the key to controlling the spread. Testing alone won't get us there.

 

That bigger point I certainly agree with.  

[TarynB]

1 hour ago, Pen said:

 

That bigger point I certainly agree with.  

Here's a link to a commentary Osterholm wrote approx a month ago about what he's actually said (and not said) about masks. Ironically, his position has been mischaracterized by folks on both sides. And so he's come out with a stronger message so hopefully his position is more clear to everyone. He works hard to avoid political issues, which makes some people dislike him, but like him or not, he genuinely appears to be data-driven.

As to the reference above about the illustrative single mom with two kids who could be a person of color and shares an apartment with her elderly parents and has to go out to work to provide for her family . . . the context of that example was coming from a place of empathy (and advocacy), not a slam or an insult. 

Edited August 22, 2020 by TarynB

[Pen]

33 minutes ago, TarynB said:

Here's a link to a commentary Osterholm wrote approx a month ago about what he's actually said (and not said) about masks. Ironically, his position has been mischaracterized by folks on both sides. And so he's come out with a stronger message so hopefully his position is more clear to everyone. He works hard to avoid political issues, which makes some people dislike him, but like him or not, he genuinely appears to be data-driven.

 

"Cloth masks, I think are at the very bottom of the list. They have little impact if any. But they've become basically something that people feel like they have to do or want to do it. If they want to do it, go ahead."

In many areas, though, it's no longer a matter of whether you want to do it or not. In Michigan, masks are mandatory in any public place, including grocery stores. The mayor of Stillwater, Okla., rescinded a mask order after it was discovered that employees trying to enforce it were threatened with physical violence.

Dr. Osterholm ended his discussion about masks on The Morning News with Dave Lee by saying they just aren't that helpful in normal public places.

"I can tell you right now I don't believe that they play any major role in either preventing me from getting infected if I use it or if I am infected and don't know it. I don't have any symptoms. They don't protect those around me from using it."

I can’t find the original recording to verify.

but here’s one that’s still available:

 

 

https://youtu.be/rlGJLVEf3AE

 

Asked what can the average person do, the interviewer says he sees people walking around with masks and gloves on, is that nonsense?

Osterholm answers “Largely”  

and yes, he goes on with more detail, and nuance, but  the initial basic takeaway that I think can be heard from what he said is masks are largely nonsense.

 

ymmv

 

Edited August 22, 2020 by Pen

[TarynB]

27 minutes ago, Pen said:

 

"Cloth masks, I think are at the very bottom of the list. They have little impact if any. But they've become basically something that people feel like they have to do or want to do it. If they want to do it, go ahead."

In many areas, though, it's no longer a matter of whether you want to do it or not. In Michigan, masks are mandatory in any public place, including grocery stores. The mayor of Stillwater, Okla., rescinded a mask order after it was discovered that employees trying to enforce it were threatened with physical violence.

Dr. Osterholm ended his discussion about masks on The Morning News with Dave Lee by saying they just aren't that helpful in normal public places.

"I can tell you right now I don't believe that they play any major role in either preventing me from getting infected if I use it or if I am infected and don't know it. I don't have any symptoms. They don't protect those around me from using it."

I can’t find the original recording to verify.

but here’s one that’s still available:

 

 

https://youtu.be/rlGJLVEf3AE

 

Asked what can the average person do, the interviewer says he sees people walking around with masks and gloves on, is that nonsense?

Osterholm answers “Largely”  

and yes, he goes on with more detail, and nuance, but  the initial basic takeaway that I think can be heard from what he said is masks are largely nonsense.

 

ymmv

 

I can see that you're firm in your opinion, and also that you didn't bother to read the link I provided.

As Dr. O wrote in the very first lines of the linked commentary, "Science, when done well, can be messy, imperfect, and slower than we wish. And it's ever-evolving." Yes, he said things back in March, which you referred to above, that he has since changed as more data has become available. As have many others. He's data-driven. If you want to have the last word, that's fine, and I don't care either way about your position, so I'm bowing out now, but what you've quoted from March is outdated information. Things have changed a LOT since March.

Edited August 22, 2020 by TarynB

[Pen]

13 hours ago, Pen said:

 

Agh.  😡

Note: I only got part way through the long interview and may change this later, but I am commenting mainly on your own summary above particularly the bold part. And listening to that area of what he said. 

I  agree that there is major message confusion.  And Osterholm himself is part of that imo.

Take masks for example.

I know Fauci first came out against them and then later did a 180.

 

My recollection is that Osterholm didn’t do a complete 180, but he was fairly negative or at least not positive about masks on a quite similar basis to what you wrote above about dipsticks.  Masks, as I understood what he had conveyed (which could be wrong but if wrong means he himself may not be as clear in his messaging as he may think) would give a false sense of security, while at best they would only make it safe to do something like ride in a car with someone (positive) for 20 minutes instead of 10 minutes. 

That’s not necessarily incorrect. But it  (the false sense of security argument) is being used by people of good will and reasonable intelligence as a reason not to mask.   

So then as Masks were learned to probably help quite a lot, maybe around late July,  Osterholm came out and says he didn’t tell people not to mask. No. In anything I heard He did not directly say don’t mask.  But he said things that clearly gave that impression, that masks could give false sense of security and thus conveyed a sense of negativity toward masks. .   And he had a tone about it that made it sound to me like he thought it would be akin to thinking a layer of bubble wrap would help to protect from a fall off a tall building.  A “wear a mask if you want, but don’t expect it to help any” tone. 

 

So far as I can tell, young adults who believe their risky behavior is not risky, or who deliberately embrace risk are already doing that. Would dipstick tests increase that? Idk. But there are a lot of people in many many circumstances who won’t use such tests to justify high risk behavior and for whom it might, like masks, be another potentially extremely helpful tool to have.  

 

I think there are huge numbers of responsible people who could make good use of it by testing every few days even if completely Asymptomatic in terms of helping to decide even whether to go in to work or whether to send children to school and that it could be a huge help. I don’t think MO is correct that the world is divided between ultra-risky behavior young adults and people in tiny bubbles and who can stay that way indefinitely as the only ones who would use such tests. 

 

ETA And his argument that sounds like he thinks it would be especially bad for low income and so on and African Americans he mentioned specifically to be able to know whether they are positive because they cannot isolate is especially bizarre and or egregious sounding to me.  I think his hypothetical single mother might want to keep distance from her own children as much as she could for 14 days if she knew she were positive, and that we as a society might want to use other resources to help such a family to confirm the positive and to be able to isolate for days most likely to spread infection—not to prefer making it hard to know that there’s a positive so that they carry on as usual.  (Around 52 minutes point.)   I can certainly say for myself as a single parent with somewhat reduced resources that I would certainly want to know if my child or myself were positive and to do what could be done not to spread infection to each other (or at least lower the viral load—better no hugs for 2 weeks than both people really sick) and to do what one could to not spread infection to others.  Even if someone has to keep working, I don’t see how not knowing helps, other than  an “ignorance is bliss” type argument. 

 

Imo, approve the home dipstick type tests Give them a nice big black box warning that a negative result does not mean definitely negative. So don’t go do risky things based on a negative result. False negatives already exist for the current tests, which in many places are still very hard to access, and slow to get results for.  

And for some people even if testing does not have major hoops there are problems like living in a rural area 3 hours drive or more from nearest test location. Should one drive oneself if feeling ill? Should someone else drive the ill person using masks that only give 20 minutes in car protection?  

 

Is Osterholm leaving epidemiology and moving into psychology ?  What is his expertise in psychology?

 

even if he is strictly in his own area of expertise, Experts can make major errors.  

For a non current example,  Benjamin Rush (I think it was from books on viruses I have been reading) told people that yellow fever was caused by foul air and told people to flee yellow fever areas — thus spreading infectious disease far and wide.

 

 

@TarynB

I know that it is old.

My initial statement, quoted above, to which I thought you were responding was that  he had not done a complete 180 on masks like Fauci did, but he had similarly substantially changed his stance on masking —

And the “old” statements were trying to show what I meant by his change from earlier statements, so yeah, of course it was old. 

I brought up the early  negative position on masks  that imo  

led to more spread than needs have been because I think the  his negative stance on dipstick tests now is quite similar. 

I think in numerous ways there is a problem with  official positions that go for a don’t use, or even don’t allow use of something in cases where gov approval is needed,  that could potentially help  (masks, dipstick test, ...)  initial stance. 

It seems to be an anti-precautionary principal approach.   

 

[Laura Corin]

Real understanding of exponential growth (often unrelated to intelligence or education) and attitudes to the risk of Covid

https://www.bbc.com/future/article/20200812-exponential-growth-bias-the-numerical-error-behind-covid-19?utm_source=pocket-newtab-global-en-GB

[Pen]

44 minutes ago, Laura Corin said:

Real understanding of exponential growth (often unrelated to intelligence or education) and attitudes to the risk of Covid

https://www.bbc.com/future/article/20200812-exponential-growth-bias-the-numerical-error-behind-covid-19?utm_source=pocket-newtab-global-en-GB

 

Good article.  Thanks!!!

Yes.

And as homeschoolers, it is a great time to self educate and teach our children about exponential growth.  

 

I don’t know if it’s correct that 99% of Americans  would have embraced all distancing measures if they had understood. TBH   I think probably not.  But it at least could be tried to convey the concept to people who do not understand it and maybe it could help now.   If even 10 or 40 % additional people come to understand, and have that substantially influence behavior rather than a “my rights, you can’t make me” or similar attitude, that, coupled with exponential help from every case spread thus averted could still help hugely. 

 

Also a problem perhaps in missing the potential for  various mitigation factors that may be insufficient alone, but together can help with exponential decrease.  Because even when numbers are high, the way exponential decrease works, they can come down, more quickly than one might think without such an understanding. Even if not immediately decreasing by half and half again, it can still happen.  

What I see a lot of is a defeatism: Like case spread is already  so high, there’s no more point. Statements like, “well everyone is going to get it, so might as well ____”       And I read that here in some posts on WTM too. 

 

But just as the weeds in the pond can rapidly fill via exponential growth, so too they can rapidly recede with exponential decrease.  And that too needs to be understood. 

 

 

And, in fact, part of my issue with Osterholm and others as per the posts above—if behaviors and strategies  like mask wearing, and hand washing and dipstick tests or  _____ , can help either to reduce exponential growth or to help toward exponential reduction, an attitude perhaps especially from the science “experts” that says phooey to Masks, handwashing, etc (unless / until proven months later that it had an at least incremental benefit)  can lead to lack of using precautions that can become an enormous number of cases as the increment that might have mitigated,  but was not,  gets turned exponential over time.  

Far better, imo, to have wiped groceries and then discover that perhaps it was not needed, then to tell people they are being stupid to do it , until months later if it turns out it should have been done after all.

 Even something that doesn’t stop a lot of spread, but still does stop a portion of spread helps.  Even if just 2 early cases get stopped by a reasonable behavior, like, say,  handwashing,  it can have helped to have stopped those two cases from themselves expanding exponentially, 2, 4, 8, 16 ... and in a few months it’s a million. 

 

Imo, Precautionary principle is very important when growth is exponential.  Waiting 3 months or 3 years for studies to show that homemade masks could help some after all means a lot of probably excess deaths and long term sickness may have happened in the interim.  And the “experts” keep on doing that.  

 

It’s hugely important imo to look at the early bit of a hockey stick upward graph shape of something bad like pandemic spread happening and immediately take action.  

Moreover, and as we cannot go back to January or March, but Are where we are now, It is also important IMo to look at an early bit of exponential decrease happening and build on that improvement,  keep the positive trend going rather than discount it or stop the helpful actions or stop looking for yet more actions, behaviors, tools, etc.  that can add to the decrease trend. 

[vmsurbat1]

I posted this on another thread, but I highly recommend the delightful children's book, A Grain of Rice to aid anyone in understanding the power of exponential growth....

 

[Bootsie]

46 minutes ago, Pen said:

But just as the weeds in the pond can rapidly fill via exponential growth, so too they can rapidly recede with exponential decrease.  And that too needs to be understood. 

 

Mathematically, this isn't exactly the same as what happens with the total number of cases.  We can't have a negative case rate.  We can reduce the R0, but the lowest R0 can go is zero.  For the pond you have two things--the number of weeds added each day (the number of new cases) and the cumulative number of weeds (total cases).  For the weeds to recede, there has to be some weeds that are there that disappear--in other words, you have to have a negative number of weeds in a new day.  An R0 less than 1 gives you a smaller and smaller decrease in cases each day, not an increasing decrease in cases each day (which you would need for an exponential decrease). 

[Pen]

Pond full of weeds can start losing them (say with the coming of cold weather, and an animal that likes to eat them, and a beaver turning them into dams) in much the same way it can fill...   One day a few are gone and then the next day even more and the next day even more...  as more cold comes and the animals bring some friends... and one day a pond that was chuck full in mid summer is nearly empty, and a few days after that can be all gone...     this is not really a theoretical mathematical issue - it is irl nature that I have personally observed 

in theory it should perhaps be like an Achilles Paradox and never reach zero.

 Irl a biological growth (whether in one single host or more broadly in a community or even in an epidemic) can go down to zero.   Very very very Sad if it’s Steller’s Sea Cows, better at least from human POV if it’s a pathogenic virus.    

A body gets sick, virus multiplies... if body starts to heal, virus inside usually decreases in number. (Assuming it isn’t going into a dormant stage). ...   similar happens also with groups...

Edited August 22, 2020 by Pen

[Ausmumof3]

bno - NEW: Italy reports 1,071 new cases of coronavirus, biggest one-day increase since lockdown ended in May
 

 

[Pen]

13 minutes ago, square_25 said:

With an R0 below 1, you have exponential decrease in the NEW cases. Obviously, the cumulative cases don’t go down.

 

Right. Cumulative cases obviously don’t go down. New cases go down— and also existing cases resolve as deaths, recovery (or long term sequelae) ...   

[Ausmumof3]

2 cases for qld today

208 for Vic. 17 deaths.  They are three weeks into the lockdown.  Apparently testing is down as well unfortunately.  

[Bootsie]

1 hour ago, square_25 said:

With an R0 below 1, you have exponential decrease in the NEW cases. Obviously, the cumulative cases don’t go down.

If you have an R0 of .5--you have 1000 new cases, then 500 new cases, then 250 new cases, then 125 new cases, then 62.5 new cases--that is less than a linear decline in new cases, not an exponential decrease.

[Bootsie]

1 hour ago, Pen said:

Pond full of weeds can start losing them (say with the coming of cold weather, and an animal that likes to eat them, and a beaver turning them into dams) in much the same way it can fill...   One day a few are gone and then the next day even more and the next day even more...  as more cold comes and the animals bring some friends... and one day a pond that was chuck full in mid summer is nearly empty, and a few days after that can be all gone...     this is not really a theoretical mathematical issue - it is irl nature that I have personally observed 

in theory it should perhaps be like an Achilles Paradox and never reach zero.

 Irl a biological growth (whether in one single host or more broadly in a community or even in an epidemic) can go down to zero.   Very very very Sad if it’s Steller’s Sea Cows, better at least from human POV if it’s a pathogenic virus.    

A body gets sick, virus multiplies... if body starts to heal, virus inside usually decreases in number. (Assuming it isn’t going into a dormant stage). ...   similar happens also with groups...

The perspective depends upon whether you are looking at new cases, cumulative cases, or active cases.  The number of new cases can decline (and to zero), the number of active cases can decline (and to zero), the number cumulative cases can, at best, remain constant.  

[Bootsie]

13 minutes ago, square_25 said:

A linear decrease in new cases makes no sense, anyway — it would soon take you into the negatives. I would call exponentiation with a base under 1 exponential decrease. It’s much faster than decrease proportional to 1/x, say.

This is what your decrease would look like if you had an R0 of 0.5.  If you have 1000 people who infect 500, who infect 250, etc.  Is that what you would consider an exponential decrease?  I thought exponential decrease would be that at each round you would have a larger decrease in cases than in the previous round (like in the exponential increase each round gets more and more pronounced)

 

[Pen]

2 hours ago, Bootsie said:

If you have an R0 of .5--you have 1000 new cases, then 500 new cases, then 250 new cases, then 125 new cases, then 62.5 new cases--that is less than a linear decline in new cases, not an exponential decrease.

 

Not what tends to happen IRL with biological situation afaik

 

 

greatly oversimplifying, 

the reduction itself tends to follow a typical normal exponential pattern, such as x^2 every several days or weeks— but going downward not upwards

Wherever you start say 100,000 new cases on Day 0 you don’t have 50,000 new on Day 1, 25,000 new on Day 2 etc. 

 

it starts in what often seems small and hardly perceptible drop just as exponential growth is easy to miss at first.  Something like 99,998 cases Day 1, 99,994 cases Day 2 (and actually the reduction doubling rate might be every few days or week not daily).  And at first it seems like nothing’s happening, nothing’s working just like exponential growth can seem like no big deal at first. But then “Day 6” it drops by ~ 1024 and “day 7” by another 2048 and “day 8” by around 4000, and “day 9” by around 8000, “day 10” by around 16,000, D11 by ~ 16,000, “D12” by ~ 32,000, D13 by ~ 64,000 ...   

It’s not simple of course, and almost certainly not going to drop daily like that with major pandemic...

[Bootsie]

2 minutes ago, Pen said:

 

Not what tends to happen IRL with biological situation afaik

 

 

greatly oversimplifying, 

the reduction itself tends to follow a typical normal exponential pattern, such as x^2 every several days or weeks— but going downward not upwards

Wherever you start say 100,000 new cases on Day 0 you don’t have 50,000 new on Day 1, 25,000 new on Day 2 etc. 

 

it starts in what often seems small and hardly perceptible drop just as exponential growth is easy to miss at first.  Something like 99,998 cases Day 1, 99,994 cases Day 2 (and actually the reduction doubling rate might be every few days or week not daily).  And at first it seems like nothing’s happening, nothing’s working just like exponential growth can seem like no big deal at first. But then “Day 6” it drops by ~ 1024 and “day 7” by another 2048 and “day 8” by around 4000, and “day 9” by around 8000, “day 10” by around 16,000, D11 by ~ 16,000, “D12” by ~ 32,000, D13 by ~ 64,000 ...   

It’s not simple of course, and almost certainly not going to drop daily like that with major pandemic...

But the only way I can see that happening is if there is a significant fall in the R0 that continues to fall.  Is that a reasonable assumption?  

The R0 can remain constant and we will see exponential growth to the upside.  

[Pen]

The graph that I am watching for tends to look like an upside down of the hockey stick that signifies exponential growth, the almost flat part that touches the ice seeming hardly to do anything, then turning sharper toward handle down as momentum increases.  Or a graph that is more like a thick beaver tail look .

 

[Pen]

3 minutes ago, Bootsie said:

But the only way I can see that happening is if there is a significant fall in the R0 that continues to fall.  Is that a reasonable assumption?  

The R0 can remain constant and we will see exponential growth to the upside.  

 

 I am not understanding what you mean by bolded parts. 

Afaik the Reproduction rate must be less than 1. 

 

[Bootsie]

5 minutes ago, Pen said:

The graph that I am watching for tends to look like an upside down of the hockey stick that signifies exponential growth, the almost flat part that touches the ice seeming hardly to do anything, then turning sharper toward handle down as momentum increases.  Or a graph that is more like a thick beaver tail look .

 

Are you picturing something like this?  (I live in a climate without hockey sticks or beavers, so I am having trouble picturing it)

[Bootsie]

2 minutes ago, Pen said:

 

 I am not understanding what you mean by bolded parts. 

Afaik the Reproduction rate must be less than 1. 

 

If you have 1000 people infected in Round 1 who each infect .5 of a person (reproduction rate of less than 1) the next round has 500 people infected.  If the reproduction rate remains at .5, the next round has 250 people infected.  The next round would have 125 people infected...

So, in the first round you get the new cases fall by 500, then the next round new cases fall by 250, then the next round cases fall by 125--each round the new cases fall by a smaller number--not a larger number.  

The only way that a round could have a larger decrease than the previous round is for there to be a significant decrease in the reproduction rate.  

[Bootsie]

8 minutes ago, Pen said:

 

 I am not understanding what you mean by bolded parts. 

Afaik the Reproduction rate must be less than 1. 

 

If you are asking about 

The R0 can remain constant and we will see exponential growth to the upside.  

If R0 is 1.5 and you have 1000 people infected, the next round 1500 people are infected, and then the next round 2250 new cases occur--this is because although the reproduction rate is remaining constant you have more infected people (a larger base) to replicate.  

 

[Pen]

3 minutes ago, Bootsie said:

Are you picturing something like this?  (I live in a climate without hockey sticks or beavers, so I am having trouble picturing it)

 

Not necessarily exactly, but closer to this than the previous one.  I, of course, expect real life graphs to be spikey and irregular — but the general concept of gradual at first, then getting to a bigger drop (especially on 7 day averaged versions) is closer.  

A reproduction rate irl may not be anywhere near as consistent as in a math model.  Maybe it is 0.98 for a few days, then 0.87 for a few days, then people get complacent and party more and it goes above 1 for a few days....

[Jean in Newcastle]

Perhaps I am dense but I don’t understand why there would be an exponential decrease. The reason that there is exponential increase is because the virus infects available hosts at a certain rate. But protective measures takes away available hosts. So if there are no available hosts within a certain period of time (14 days or whatever it may be) then that line of infection is extinguished. But it’s not like those lines are going to be extinguished in some mathematically elegant way, right? Because it’s a function of human behavior influencing the virus which is still going to try to replicate if it has a viable host (whatever makes that the case). 

[Bootsie]

2 minutes ago, Jean in Newcastle said:

Perhaps I am dense but I don’t understand why there would be an exponential decrease. The reason that there is exponential increase is because the virus infects available hosts at a certain rate. But protective measures takes away available hosts. So if there are no available hosts within a certain period of time (14 days or whatever it may be) then that line of infection is extinguished. But it’s not like those lines are going to be extinguished in some mathematically elegant way, right? Because it’s a function of human behavior influencing the virus which is still going to try to replicate if it has a viable host (whatever makes that the case). 

Human behavior will change the R0.  You must have an R0 under 1 for the number of new cases to decline from one round to another.  This could be due to the nature of a virus (which will eventually die out) or because of changed behavior that significantly decreases opportunity for hosts and lowers R0.  I think what we are seeing, however, is that as soon as that behavior changes, the R0 goes back to what it was, because it isn't the overall nature of the virus that is changing and causing it to fall.  In the real world, it isn't a perfectly exact mathematical relationship, but the basic principle of what is happening holds.  

[Pen]

Just now, Jean in Newcastle said:

Perhaps I am dense but I don’t understand why there would be an exponential decrease. The reason that there is exponential increase is because the virus infects available hosts at a certain rate. But protective measures takes away available hosts. So if there are no available hosts within a certain period of time (14 days or whatever it may be) then that line of infection is extinguished. But it’s not like those lines are going to be extinguished in some mathematically elegant way, right? Because it’s a function of human behavior influencing the virus which is still going to try to replicate if it has a viable host (whatever makes that the case). 

 

There by no means necessarily would need to be an exponential decrease. However, it can happen. 

A petrie dish could have a sudden wipe out of the colonies growing there, or a slow linear decrease, or what I was talking about ... all are possible. 

The irl increase is actually not a perfect mathematical thing either except when able to be looked at as a large aggregate picture.   Each person does not infect exactly 2 others, or whatever the R0 is.  One person may infect 85 others and many people infect one or none.  

 

[Bootsie]

9 minutes ago, Pen said:

 

Not necessarily exactly, but closer to this than the previous one.  I, of course, expect real life graphs to be spikey and irregular — but the general concept of gradual at first, then getting to a bigger drop (especially on 7 day averaged versions) is closer.  

A reproduction rate irl may not be anywhere near as consistent as in a math model.  Maybe it is 0.98 for a few days, then 0.87 for a few days, then people get complacent and party more and it goes above 1 for a few days....

The only way to get a curve that is shaped somewhat like this is for the R0 to be SIGNIFICANTLY dropping over time.  This is one of the things that I think is so tricky--as we lower the R0, I think it gets harder and harder to lower it further.  We can give up some of the easy things and take some basic precautions and make a big impact.  But, the difference we get from the hard work of lowering R0 from .9 to .8, for example, is much less dramatic than the impact we get from dropping the R0 from 1.1 to 1.0

[Pen]

3 minutes ago, Bootsie said:

Human behavior will change the R0.  You must have an R0 under 1 for the number of new cases to decline from one round to another.  This could be due to the nature of a virus (which will eventually die out) or because of changed behavior that significantly decreases opportunity for hosts and lowers R0.  I think what we are seeing, however, is that as soon as that behavior changes, the R0 goes back to what it was, because it isn't the overall nature of the virus that is changing and causing it to fall.  In the real world, it isn't a perfectly exact mathematical relationship, but the basic principle of what is happening holds.  

 

Yes. Human behavior substantially changes the R0. 

The virus can change too of course, and so can the host environment or the external environment.  But what we are substantially seeing is things like travel or close contact etc that are part of human behavior that make the main changes so far with this non rapidly mutating virus.  

[Bootsie]

1 minute ago, Pen said:

 

There by no means necessarily would need to be an exponential decrease. However, it can happen. 

A petrie dish could have a sudden wipe out of the colonies growing there, or a slow linear decrease, or what I was talking about ... all are possible. 

The irl increase is actually not a perfect mathematical thing either except when able to be looked at as a large aggregate picture.   Each person does not infect exactly 2 others, or whatever the R0 is.  One person may infect 85 others and many people infect one or none.  

 

How in the situation of humans and COVID could you have an exponential decrease without a falling R0?  I understand that irl we do not get a perfect mathematical relationship and that R0 is an average over a community, and does not refer to one person's spread.  But, I am having difficult coming up with an example of what would have to happen to have an exponential decrease in new cases without having a significantly declining R0.  The exponential growth to the upside is not dependent upon a changing R0.

[Jean in Newcastle]

11 minutes ago, Bootsie said:

Human behavior will change the R0.  You must have an R0 under 1 for the number of new cases to decline from one round to another.  This could be due to the nature of a virus (which will eventually die out) or because of changed behavior that significantly decreases opportunity for hosts and lowers R0.  I think what we are seeing, however, is that as soon as that behavior changes, the R0 goes back to what it was, because it isn't the overall nature of the virus that is changing and causing it to fall.  In the real world, it isn't a perfectly exact mathematical relationship, but the basic principle of what is happening holds.  

So the virus will eventually die out because of mutations that lower the RO?

[Bootsie]

Just now, Jean in Newcastle said:

So the virus will eventually die out because of mutations that lower the RO?

If a virus has an R0 of less than 1, it will eventually die out--I am not sure if virologists think that is a possibility with this virus or not.  

[Pen]

32 minutes ago, Bootsie said:

How in the situation of humans and COVID could you have an exponential decrease without a falling R0?  I understand that irl we do not get a perfect mathematical relationship and that R0 is an average over a community, and does not refer to one person's spread.  But, I am having difficult coming up with an example of what would have to happen to have an exponential decrease in new cases without having a significantly declining R0.  The exponential growth to the upside is not dependent upon a changing R0.

Ok. 

It’s probably the case that if I think about it, the R0 does end up going down.

But not necessarily that more and more harder and harder things need to be done to achieve that. (So long as complacency and stopping doing what can be done isn’t thrown to the wind.) At some point if the 100,000 per day are declining from human behavior, there may also be increase in herd immunity, medicines,  and other changes that may help decrease new cases—  or new severe cases .   At some point the host-virus relationship may also change (which could be either for the better or the worse). 

  Or thinking about it like a weed  pond where there’s spread or decline by seeding changes (most basic reproduction rate concept if a single plant on average puts out two viable seeds versus less than one)... but there can also be change downward by something like the beavers pulling out the plants (I do live in a beaver area and it is amazing how quickly they can transform a landscape), which probably does decrease R0 , but at least seems somewhat different.  Each plant could seed itself on average just as much as it used to , but the removal of plants to do the seeding helps very significantly to clear the pond.   Especially if perhaps distance is a factor, (sexually reproducing  weeds that need to be pollinated with a nearby one)  the clearing may lead to more distance which itself helps to decrease the R0.  

In virus situation,  As there are fewer and fewer people from whom to catch it in a community, instead of more and more, that can help. 

[lewelma]

So in the past 10 days we have tested 10% of Auckland and a good percent of the rest of the country. This is what has been found:

1) They have not found the source for the cluster of 93 people that started at the Amicold cold storage shipping company. The genome does not match the 1st wave (so not from 100 days ago), and it does not match any imported cases from quarantine.  Plus, all environmental testing of Amicold came back negative.  They have contact traced 2000 people and have massive testing in any regions where they expected spread.  There was 1 new case today that was a family member of a previous case, so expected. They believe that they have ring fenced this cluster, and have put all the positive cases and their families into quarantine.

2) They have tested all 5000 of the quarantine/dock/airport staff, and have found 1 positive test.  This test is not linked to the cluster, but is linked to an imported case.  They have used swipe cards and CCTV and know that the maintenance guy went in an elevator 2 minutes after the imported case was in it.  That is the only link they can find.  The maintenance guy has not passed it to anyone. This has shown that the quarantine procedures are robust and well implemented, but also that this virus is tricky given it was passed possibly through the air of an elevator when the two people were sequential and not concurrent. 

3) I think most of us are expecting that Auckland will come out of lockdown on Wednesday, 2 weeks after going in. Basically, the government had a resurgence plan, and acted swiftly and competently to implement it.  There is a good possibility that by acting fast and hard, the job will be done, and we can go back to regrowing our economy. Keep in mind that the largest city in the country was locked down after 4 cases were found, and was locked down within 5 hours of the positive results from the family coming back. When I say fast and hard, I'm not kidding.  The government will decide tomorrow about 1) the Auckland lockdown (work from home order and school closures) and 2) the rest of NZ's 'be careful' status which limits gatherings to under 100, and turns bars into seated restaurants. 

4) The PM delayed the election by a month to give all parties a chance to do their politicking without the largest city being in lockdown. The PM has this right under law, so nothing fishy here.  She has said that she will not delay it again, although the electoral commission can if they deem it unsafe.

 

Edited August 23, 2020 by lewelma

[Pen]

3 minutes ago, lewelma said:

So in the past 10 days we have tested 10% of Auckland and a good percent of the rest of the country. This is what has been found:

1) They have not found the source for the cluster of 93 people that started at the Amicold cold storage shipping company. The genome does not match the 1st wave (so not from 100 days ago), and it does not match any imported cases from quarantine.  Plus, all environmental testing of Amicold came back negative.  They have contact traced 2000 people and have massive testing in any regions where they expected spread.  There was 1 new case today that was a family member of a previous case, so expected. They believe that they have ring fenced this cluster, and have put all the positive cases and their families into quarantine.

2) They have tested all 5000 of the quarantine/dock/airport staff, and have found 1 positive test.  This test is not linked to the cluster, but is linked to an imported case.  They have used swipe cards and CCTV and know that the maintenance guy went in an elevator 2 minutes after the imported case was in it.  That is the only link they can find.  The maintenance guy has not passed it to anyone. 

3) I think most of us are expecting that Auckland will come out of lockdown on Wednesday, 2 weeks after going in. Basically, the government had a resurgence plan, and acted swiftly and competently to implement it.  There is a good possibility that by acting fast and hard, the job will be done, and we can go back to regrowing our economy. Crossing fingers.  The government will decide tomorrow about 1) the Auckland lockdown (work from home order and school closures) and 2) the rest of NZ's 'be careful' status which limits gatherings to under 100, and turns bars into seated restaurants. 

4) And the PM delayed the election by a month to give all parties a chance to do their politicking without the largest city being in lockdown. The PM has this right under law, so nothing fishy here.  She has said that she will not delay it again, although the electoral commission can if they deem it unsafe.

 

Thank you for update!!!

Wow! That is amazing good tracking and investigating and quarantining.  

 

The cluster seemingly from nowhere, not even matched genome, is really weird. 

 

I guess it could be happening elsewhere like that too and who would even know in the midst of thousands of new cases.  🤷‍♀️

 

Do you know, Did they look at if some non human animal could have caught it from some past human source and then passed it on (with genome changes)? Or a one spot of major package contamination but not general contamination to be found elsewhere on packaging? 

Do they know if genome is brand new or exists in some other country?   If so what other country ? And where was the cold shipping from? And how long stored or in shipping before it was handled? Or too much stuff from many different places and different times to know? 

 

The maintenance person in elevator after infectious person is also really helpful to keep awareness of, I think.  Lots of times I think people think if they rode separately it’s okay. But a separated trip is clearly potentially still a problem.  I think some other cases elsewhere were also supposed to have had only same elevator, but not same time as a link.  

[lewelma]

23 minutes ago, Pen said:

Do you know, Did they look at if some non human animal could have caught it from some past human source and then passed it on (with genome changes)? Or a one spot of major package contamination but not general contamination to be found elsewhere on packaging? 

Do they know if genome is brand new or exists in some other country?   If so what other country ? And where was the cold shipping from? And how long stored or in shipping before it was handled? Or too much stuff from many different places and different times to know? 

They are not clear if the Amicold employee was the first case. The index case is now considered infected on the 31st of July, 10 days before he got tested (he had been home for 9 days on sick leave). That was long enough time delay that if it had come in on cold storage, they would not have been able to find active virus by the time they were testing.  They know that this strain is from the UK or possibly Australia.    

[lewelma]

43 minutes ago, Pen said:

Wow! That is amazing good tracking and investigating and quarantining.  

Yes!  I have been very impressed!  They did a very good job planning, and then actually implemented the plan. They found it about 10 days after the first person caught it (they think), and the cluster grew to 93 people by day 20 even with the city in lockdown for the last 10 days. What a nice example of exponential growth!

Once elimination was accomplished in May, it is now cheaper for us to lock down a city for 2 weeks and spend a ton on testing to reach elimination status again. Our economy really got going again quite rapidly during the 100 days without Covid.  My guess is that they may start surveillance testing of waste water so they can catch it even earlier than they did. Our testing had also fallen off because people just got complacent.  So I'm guessing there will be more public awareness and government encouragement to get tested if you have symptoms. 

We have also been put in the purchasing pool with Australia and the Pacific Islands to buy the vaccine coming out of Oxford. 

 

Edited August 23, 2020 by lewelma

[Ausmumof3]

3 hours ago, Jean in Newcastle said:

So the virus will eventually die out because of mutations that lower the RO?

Or eventually would become like seasonal flu or other seasonal corona viruses that come and go as the number of non immune people builds up and then you have a little outbreak and it goes down again.  That doesn’t mean it’s like the flu right now of course just that without a vaccine that might be what would happen.

[Bootsie]

2 hours ago, square_25 said:

Yes, I’d call that exponential decrease. As I said, it’s much faster than decrease proportional to any rational function (a ratio of polynomials.) It’s the standard meaning of exponential decrease, AKA exponential decay:

https://mathworld.wolfram.com/ExponentiallyDecreasingFunction.html

This is an exponentially decreasing function in that the decrease each step of the way becomes exponentially smaller.  So, each round the decreases in the number of new cases becomes smaller and smaller and smaller (exponentially).  So with this the number of new cases each round goes from 100 to 50 (50 improvement), then 50 to 25 (25 improvement, then 25 to 12.5, and so forth..

I understand the poster to be describing a decline that got exponentially bigger--so that as difference in new cases got larger and larger over time (like for 100 to 90, then 90 to 70, then 70 to 40...), like what happens with an R0 larger than 1, but I don't think that happens mathematically without a negative R0 (which is impossible).  

Mathematically, this is why the early models of flatten the curve, that showed a bell-shaped curve we so misleading--it would take an extremely dramatic decline in R0 for the right hand of the curve to decline as quickly and sharply as the left hand increased.  

[AmandaVT]

13 hours ago, Bootsie said:

Are you picturing something like this?  (I live in a climate without hockey sticks or beavers, so I am having trouble picturing it)

 

12 hours ago, Pen said:

 

Not necessarily exactly, but closer to this than the previous one.  I, of course, expect real life graphs to be spikey and irregular — but the general concept of gradual at first, then getting to a bigger drop (especially on 7 day averaged versions) is closer.  

A reproduction rate irl may not be anywhere near as consistent as in a math model.  Maybe it is 0.98 for a few days, then 0.87 for a few days, then people get complacent and party more and it goes above 1 for a few days....

I feel like NY has a pretty good visual for a sharp decrease in cases.