14 day downward trend - Rinse, Repeat?

[G.D. Gentleman]

Simple question that I doubt (but hope) will receive a simple answer:

A 14 download trend while an area (let's say a province or state) is observed while in a consistent level of lockdown.


Some economic activities are opened up, generating more in person shared space activity - with best effort to socially/physically distance.

We see an uptick in active cases of the virus.

Do we now roll back those opening activities and monitor again for 14 days? Rinse and repeat, hoping it works the next attempt? Or the next attempt? Or the next attempt?


Lots of discussion on 'opening too soon' and 'open now crowd' - I'm not part of either.

So my actual final question for this thread is:

Those who speak of the 14-day trending model is to explain how the modelling works when the lockdown levels change and therefore the modelling source data changes?


Thanks in advance.

 

[Valcazar]

I don't know what version Ontario is using. But of the many phased plans I've seen, most use some kind of trigger for moving back to phase 1. The AEI plan has sustained rise in cases for 5 days as a trigger, for instance. I haven't seen any that require moving back based on a one day blip.

 

[G.D. Gentleman]

I don't know what version Ontario is using. But of the many phased plans I've seen, most use some kind of trigger for moving back to phase 1. The AEI plan has sustained rise in cases for 5 days as a trigger, for instance. I haven't seen any that require moving back based on a one day blip.

Thank you Valcazar.

5 day sustained rise of ### amount per day makes sense (###=some calculated amount the experts have come up with).

You nailed it on the head - we don't know what measurements the Ontario government is using - at least you and I - perhaps the members more familiar with the 14 day trend model design has seen in publication somewhere what the calculation is?


It's tough to understand that a few thousand citizens go to a park on Saturday and in turn now a province of 14 Million+ has impacted with delays of any further opening steps being considered - heck those in the park haven't had time yet to actually get sick, get tested and be part of the increase in case numbers (yet, I know) - it's a crazy time we live in now.

And yes I know the rise in cases is the driving force of the government delaying the next opening steps (and considering a possible rollback) - not just those who went to the park on Saturday, which is really just a media frenzy thus far - but the news and Ford himself do like to put 'blame' on them for sure. Reality is the numbers are going up (we all see that) and we are getting daily updates of the impact they are having on all of us.


Back to my original question - would like to understand more how the 14-day model is adjusted/restarted/other when lockdown situations are approved to be changed.

 

[bebe]

CBC interviewed one epidemiologist today, in his opinion the number of new cases in Ontario has remained flat for the last four weeks.. The little ups and downs with the reporting of the numbers meant little to him.

The 14 day decline is a red herring.

Now, doggystyle99 can chime in with his vast knowledge regarding: "significant decline of new cases for 14 days is required before moving onto stage 2." Maybe he can answer all of your questions about it.

You might recall stage 1 started without this magical and significant 14 day decline of new cases being achieved. Stage 1 was driven by big businesses such as Construction telling Ford to get a move on and he did.

 

[Valcazar]

Looking at the framework Ontario published, they aren't using the 14 day model at all. They have a set of general criteria and the health Minister is going to make a judgement call on their general sense of the numbers. There appear to be no fixed triggers at all

 

[doggystyle99]

Looking at the framework Ontario published, they aren't using the 14 day model at all. They have a set of general criteria and the health Minister is going to make a judgement call on their general sense of the numbers. There appear to be no fixed triggers at all

This is what I’ve seen that the provincial government is going to do.

“A consistent two–to-four week decrease in the number of new daily COVID‑19 cases.
A decrease in the rate of cases that cannot be traced to a source.
A decrease in the number of new COVID‑19 cases in hospitals.”

https://www.ontario.ca/page/framework-reopening-our-province

If you have another source I would love to read it.

 

[bebe]

This is what I’ve seen that the provincial government is going to do.

“A consistent two–to-four week decrease in the number of new daily COVID‑19 cases.
A decrease in the rate of cases that cannot be traced to a source.
A decrease in the number of new COVID‑19 cases in hospitals.”

https://www.ontario.ca/page/framework-reopening-our-province

If you have another source I would love to read it.

You never answered the OP's question:

Those who speak of the 14-day trending model is to explain how the modelling works when the lockdown levels change and therefore the modelling source data changes?

And I doubt very much the Government is going to follow their own guidelines when it comes to starting Stage 2. They flat out ignored it when they started Stage 1.

Curious, what qualifies as "A decrease"? it is 1 less case per day over a 14 day period or is it sometihing more. This requirement lacks a defined number that needs to be achieved.

 

[Valcazar]

@doggystyle

Same source. Notice it is a bunch of friends with no fixed numbers or definitions. It is 'they will take all these things into account". To me that means they look at all of it and make a judgment call.

 

[Malibuk]

Around a week ago they finished testing all of the long-term and old-age facilities and Ford has been calling for more diverse testing so they may finally start to see some relevant data.
Plus gross numbers need to be prorated to a common point of relative reference.

That being said, I think it is too late in terms of quantifying any current flattening of the curve.
Seasonal virus dissipation can be a much greater factor than the tiny sample size of 0.1% per day.
There are vaccine trials in the northern hemisphere that may have a big problem because of this factor.
Challenge trials might be necessary.

If they had been doing consistent broad diverse randomized testing, I think this 14 day metric could have been a relevant factor.
I also that think health system capacity trends are far more relevant than any numbers from tiny sample sizes.

I think the question is impossible to answer as there are vast degrees to increases and decreases.
How much of an increase would be considered significant? (how long is a piece of string?)

Hokkaido Japan was down to 1 or 2 new cases when they began ending their lockdown.
They saw an increase to 10 - 20 and locked down again.
While this is a huge percentage increase, I think it is a ridiculous over-reaction and they will never be able to open up if this is an overwhelming gross number for them.