Has anybody calculated the risk of someone randomly taking coronavirus over a border given a certain rate of community transmission?
If in a population of 1M there are 10 people infected unexpectedly per fortnight but 20% of the population make up 80% of the infections because of their propensity to travel and engage in risky behaviour.
If you were to have 25K travel you'd expect about ~1 to have their infection discovered outside their border in any given fortnight given these are the higher risk takers.
There's then some chance that it won't spark an outbreak-30% to 80%. But that only really determines whether than average is 3 weeks to 5 weeks to beginning an outbreak somewhere if my numbers hold up.
Which if an outbreak occurs somewhere restrictions will then need to be reimposed for 4-12 weeks-resulting in that area losing both intrastate and interstate tourism for that period of time. Yet intrastate tourism accounts for 57% of visitor nights.
Obviously I have taken a lot of simplifying assumptions above but to this point I think the economic risk of reopening state borders is high compared to potential gains if you assume elimination is the case in states with their borders closed at this time.
Well there we have it Queensland gets an active case after someone travels from Melbourne to Brisbane.

That pretty much ends the argument about the risk of coronavirus being imported from Melbourne.
Two days in a row without a community transmission case in Victoria. Makes for some double digit % chance that they have eliminated it ~10-20%.

The risk of Victoria exporting the virus has fallen ~50% since 14 days ago.
I should also point out that it was the PM who said: "Australians should expect these measures to be in place for at least 6 months." But now wants to rush commitments without the data actually being in place to back the decision.

https://www.pm.gov.au/media/update-coronavirus-measures-220320
Also on this my rough estimate is if we have to re-shutdown it will cost $200B.

The economy is currently $4B per week down theoretically although we only expect to make $2B of it back based on Treasury estimates. So delaying reopening a week may cost $2B.
Yet if we reduce the risk of another shutdown by more than 1% a week the opportunity cost says to remain shut up and reduce the risk. (It just depends what you estimate the cost of a second shutdown to be.)
One case in NSW and one case in Victoria with an unknown source. Plummeting the odds that the virus has been eliminated in either state.
The situation in Victoria and NSW has improved a lot over the last two weeks. Risks are down 75%+.

This is my tracking of unknown source cases for the last month in Victoria.
NSW reporting yesterday's unknown case as likely infected overseas.

Makes 13 days of no unexpected cases in NSW. 4 days in Melbourne.

26 days in Queensland and 33 in SEQ.
Going back over those Victorian numbers, the drop in locally acquired cases is very dramatic and unexpected really. 6 in the past week, 46 in the week before that. 31, and 51 the two weeks prior to that.
There is significant irony in the NZ DPM naming Tasmania and Queensland as states they'd be happy for NZers to fly to and Australians from. And the implication that NZ doesn't want people from NSW or Victoria yet-just like Queensland and Tasmania.
How's that Greece reopening going? 52 cases reported on Monday alone and 30 cases imported in 5 days.

From what we've seen globally it is going to be difficult for Victoria to get itself as open as states like WA and SA or NZ. The difference between low and no cases is huge.
So now we have the farce where dates get nominated but will be pushed back quicker than you can blink your eye at the sign of any outbreak.

Some people want certainty where there is absolutely none to be had.
I would also note that July 10 is essentially at the end of Victorian school holidays (so basically QLD are excluding Victorians). And July 20 for SA is excluding NSW and SA school holidays. I guess WA and Tas may go for July 31 just to see what happens in other states.
Nightclubs were in step 3 just like some interstate travel was in step 2 but every state has booted it to step 3+.

Nightclubs got the boot today by the Prime Minister so it is not like things can't get taken out of these plans.

https://www.pm.gov.au/sites/default/files/files/covid-safe-australia-roadmap.pdf
So Victoria and NSW are both clearly pursuing strategies of suppression that have failed in:

Hokkaido
Seoul
Israel
Greece
(Pick a US state)

And TBD if it is actually successful anywhere.
Meanwhile SA, WA and Tasmania could basically be NZ and let their residents do anything but are being held back merely because some want NSW and Victorian residents to be able to travel to these states.
Can't stand at the pub, can't have a full crowd, can't go dancing, can't pack out public transport, can't go to a festival and so on and so on and so on. All because we have a few desperate to see more planes in the air.
And Tokyo reports a spike up to 47 cases.

Along with Beijing locking down some parts.

The chance of another bad outbreak in NSW or Victoria still has to be viewed as likely.
Also under-appreciated before in calculating risks to other states is a bad outbreak occurring in Victoria or NSW. What happens when that occurs? States will rightly shut up their borders again. Trust gets lost and tourism operators get hammered again anyway.
Reopening with low case numbers certainly does not mean it stays that way for very long-even in some of the most successful US states. Hawaii, Vermont, Montana, Alaska.
Also here's my 7-day rolling count for Victoria with cases being announced as unknown source at the time of announcement. Up to 14 from a low of 4.

From a low of 6 locally acquired up to 31 in 7 days.
SA dropping quarantine requirements for WA, NT and Tasmania is basically completely useless for most as they still have to quarantine if they want to return back.

I'd expect that NT and maybe Tasmania will follow.
Berejiklian wonders why internal borders are a thing? Yet NSW is also a state that restricted regional travel.

How do you stop a disease spreading? Put up a border.

How is NSW different to Tas, WA and NT? They had community spread this week! Others over 2 months ago!
Seems like the Federal Governments argument that the risks of the virus are over should fail pretty easily with expert opinion that the risks are still clear and present.

Particularly with the Victorian position actually getting statistically worse over the last week.
If the court was to throw out the borders on people movement then lots of other biosecurity measures taken around Australia would be under threat that protect our agriculture sector.

It is a dumb argument that our federal government should not be backing.
They can fix it by dealing with the threat of the virus but their express strategy is to not deal with it, merely suppress it to low levels-not no risk and have explicitly stated as such that there are risks.
Also while Victoria still has a state of emergency in place you're also arguing that it should not and should remove all its restrictions which no reasonable person is arguing for.

Also saying there are no risks is a terrible public health message right now.
Victoria remains on the wrong track very clearly now but no doubt some will wish away the problem that exists in this dynamic.
Apparently Victoria reporting 11 cases that they have failed to link to a source on announcement today is good enough for the NT to reopen its border in a month.

The problem with Victoria is no-one can say whether they will have 10 or 200 local cases in the next 7 days.
Number in thousands of Victorians visiting each state in 2019:

New South Wales - 4747
Queensland - 2336
South Australia - 1384
Western Australia - 640
Tasmania - 706
Northern Territory - 296
Australian Capital Territory - 588
Victoria are definitely not on top of it.

Up to 56 local cases in 7 days and they didn't know the source on announcement for 31 of them.

Two days in a row of double digit case numbers, not achieve since May 16. Highest 7-day case total since May 18.
SA now allows Queenslanders in which actually allows Queenslanders to travel to SA given Queensland doesn't require residents to quarantine unless they have been to a hotspot. Needless to say, SA has no hotspots currently.
Is the rumoured news in Victoria surprising? No.

It is what we've seen the world over when reopening with "low" rather than no case numbers. R quickly goes above 1 and the only way to stop that is to impose restrictions again.
Is anyone to blame? No.

It is a highly viral virus. Nobody in early May knew that easing restrictions would be failing the world over from Seoul to Israel to Greece to the US.

Most authorities are making decisions based on limited information with the best of intent.
In hindsight you can do all sorts of things differently-Australia would no doubt have locked up its international border on February 1 rather than have our situation today.

The only lesson is caution and to act too early rather than too late.
In context, a very vertical line going up.
Interestingly Andrews sighted NSW potentially listing certain places as hot spots to prevent travel (this is exactly what Queensland have done).

But really it will stop all forward travel bookings as you're at risk of getting listed as a hot spot anytime.
Unfortunately it is a really bad time to book travel in advance unless you are fully prepared to cancel at the last minute which also isn't that helpful to travel operators with so much uncertainty. Taking bookings that you then have to cancel just isn't great business.
NSW remains the state taking the most risks.

At least admitting the truth in that we may have to deal with this for years. Hence there are huge benefits in stamping it out if at all possible.
I was also reminded today that NSW were going to stay in "stage 3 restrictions" for 90 days which is about today. Needless to say that they did not stay for that long and everybody seems to have moved on.
Also strange economic claims today from the PM about eliminating the virus causing greater economic damage. Well the UK is certainly far worse than NZ. And NZ's recovery is picking up pace and well in advance of Australia.
Australia is already at least a month behind NZ and are at clear risk of further slippage due to the sloppy "suppression" strategy that we have.

Also if you're a business in NZ you have far more certainty than any business in NSW or Victoria in particular.
At least WA recognises the trade-offs. You can either have everything inside your state back to normal, or accept travellers but still have to maintain social distancing etc.

Having both does not work unless the travellers are also totally clear.
Victoria are really struggling to identify the source on announcement of the case.

A few days yet to see if this is going to come down or go up but the level of unknowns does not look great.
NSW won't put in place border restrictions but want individual businesses to force restrictions on travel.

Doesn't want to be responsible. At least other states make no apologies and don't force businesses to take on what is a government responsibility.
When other states said they did not want Sydneysiders at that time Sydney had similar numbers to Melbourne right now but NSW said other states should take Sydneysiders.
Lots of silly finger-pointing at Victoria today.

All that is wrong is that reopening with low case numbers has not worked anywhere in the world. A lot of the finger pointing is coming from places that heaped pressure on them to reopen with low case numbers.
Also ironic that the most panicked state right now is NSW because they know they're carrying the biggest risk of having an outbreak like Melbourne right now.

Odds are probably something like 20% in the next 4 weeks that they get an outbreak seeded from Melbourne.
Also, let's be clear Victorians could only go to another household or to work for most of the time since April. Restaurants and cafes are only a new factor in the last 3 weeks-no conclusions can be reached yet about their safety or otherwise.
NSW continues to tell businesses not to take people from Melbourne but planes will still fly because airlines are not interested in the social good and the NSW government has taken no action to stop it.
The problem in Melbourne for them is not the absolute number of cases but the growth rate.

If they're doubling case numbers every week it will be a ~100 per day inabout two weeks time.

7-day totals

June 25: 124
June 18: 46
June 11: 13
The other problem with the absolute number of cases in Melbourne is that at some point you're bound to have a super spreader event. Maybe you can get away with it for a while but not forever and that puts you at a new higher level of cases. And it repeats.
Meanwhile NSW decides there is a border at stadiums but not at the border or airports.
So 26 local cases in Melbourne today, if you say they are going to average that everyday then ~1 in 30,000 will be infected in the next 7 days.

Sydney is getting 22 flights a day from Melbourne, so that is up to 4K people a day.
Call it 2K people a day from Melbourne into NSW. You're likely looking at an average of ~8 days until NSW discovers a case that was infected in Melbourne. Chance of causing an outbreak? Maybe 30%?

Higher infection rate or more travellers, higher chances.
If you put it at 100 cases a day and 7,000 travellers a day, you're talking a case every single day going from Melbourne to NSW. That could be the case in 2 weeks, hence why you don't take the risk and force people from Melbourne into quarantine.
Number of cases announced without knowing the source is only going up for now in Victoria.
NT announces that it will declare or let states and the AHPPC declare hot spots.

Which is basically terrible for travel as your area could get listed as a hot spot at anytime. In fact the listed Victorian hot spots are probably don't match the actual hot spots now.
Tasmania had set a date but if the health advice says no-like now-then July 24 will not be the date.

So July 24 is not the date-very simple.
I'm interested to see how Queensland kick the can down the road-say they need an extra three weeks to assess and go to July 31. And then let the Liberal states also push border reopenings back.
Not sure that anyone really believes Victoria is under control right now. Not sure that they can get out of this without further intervention. The number of new cases they cannot link with known clusters on announcement is concerning.
From when Victoria first reported 10+ cases in early May it had 11/14 days with 10+ locally acquired cases. A total of 169 with only 76 unknown.

From the first 10+ day this time, there has been 11 such days in 13 with 225 cases and 149 unknown.
Victoria is going to allow saliva tests which only pick up about 85% cases reportedly, so not really an improvement.
Test and trace is not the most effective thing. The most effective thing is to make everyone stay home.
Only being able to link 4 cases on announcement is just reflective of how far behind Victoria is right now.
Victoria wouldn't know if the untested people from hotel quarantine created community transmission. It is totally unknown. Same for the staff from there too. It is impossible to know by definition.
A suburb specific lock down in Melbourne will not work. There are already as many cases in other suburbs as there were in these hot spot ones a few weeks ago.

If they do it, they need to do Greater Melbourne.
"Many cases in the hot spot suburbs but not exclusively." Vigilance is shutting down early and putting an outbreak out, not sitting on the sidelines and letting it get worse.

We've seen the same thing around the world as places have opened up.
Last Monday Victoria reported 12 local cases. Today it is 74-the growth rate is off the charts.
Also on these risks, the risk in Sydney is clearly highly elevated with ~249 local cases in Melbourne in the last 7 days. That's 1 in 20K.

Sydney could have an outbreak that they cannot tie back to Melbourne travel history but was caused by it.
Too much rubbish around about "if other states tested more they'd have more cases". They'd have hospitalisations too and at a greater rate as they are far more open than Victoria.

Victorian testing has not increased as fast as cases either.
Nothing about Moonee Valley or its suburbs being hotspots despite that being the LGA with the third most active cases at 29 right now in Victoria.

But Cardinia still is with Pakenham being a hotspot suburb yet only has 5 active cases.
This suburb by suburb stuff is absolute whack-a-mole that is far too far behind where the virus is actually spreading. Pretty clear that our authorities are not ahead of the virus, instead badly chasing tails.
Also I doubt Queensland won't be opening its borders on July 10.

The tip off is that if they won't even allow a Queensland team to play a team that played a Melbourne team without a quarantine then Sydneysiders visiting is definitely out.
Steven Marshall is out providing political cover for Queensland announcing SA will not open the border to Victoria on July 20.
NSW will be vigilant but not vigilant enough to exclude people from Greater Melbourne entering their state but businesses should enforce it.
Too much focus on whether the Victorian number is up or down from yesterday. What we know is Victoria will report more cases this week than last week. And most likely report more again next week. So how do they stop the increase the week after next?
Another day, another surge in cases without a known source in Victoria.

7-day Locally acquired total:
June 9: 6
June 16: 38
June 23: 97
June 30: 296
July 7: ??? (if you're extrapolating it is over 600)
I expect we're going to go to daily postcode announcements. More will be the subject of this order.
Well I guess this was knowable and the certainty the other day is now definitively wrong. What a mess-there was no need to spin this about staff working at hotels with quarantine arrangements. https://twitter.com/rossleedham/status/1277059204600061952
Deputy CMO Kidd claims the Victorian model is like NW Tasmania. It is the opposite. NW Tasmania closed multiple towns through a wide region even where there were no cases.

There's places in Melbourne with cases not being shut down. This is not the same.
It also remains the case that Australia has been unable to contain an outbreak without shut downs now. If you have multiple cases there will be shut downs in those regions and they should happen instantly-not a waffle test response for 10 days.
NW Tasmania only shut down for 3 weeks and not the 4 planned in Melbourne. Tasmania also did not wait ~10 days to perform their shut down. There are massive differences between this attempt in Victoria and the success in NW Tasmania.
NSW border remains open but you'll get a massive fine or gaol if you come from a hot spot. Not clear how it is even going to be enforced.

Also the hot spots identified yesterday were different to the previous LGA list, so you can expect other hot spots to be listed soon.
Ah, still a high chance that Victoria does have more than 100 cases at least one day this week.

I'm sure there's a significant amount of cases outside hot spots too-at least double digits and this all started in single digits daily.
Three days around the same level is nothing.

Victoria spent 7 days straight between 12 and 24 cases. Now we are here less than 7 days later at around ~70.

Most places go through step changes, not incremental.
Victoria has only reported increases on the previous day 9 out of the past 14, 12 of the last 21.

To think that Victoria is flattening or peaking or stabilising is a likely terrible take. Probability that they have hit peak is maybe ~10%.
Acting CMO claims Victorian is the NW Tasmania model as well.

So risky that our public officials are describing something as the same when it clearly is not.
Also there are clearly more cases being reported outside of hot spots than there were in these hot spots two weeks ago. Postcode shut down is doomed to failure. You could use postcodes to reopen but not to shut down.
Tokyo for contrast with Victoria announced 67 cases today but 47 of them are confirmed contacts and a further 9 relate to their known problem of Shinjuku host clubs.

Victoria could only like 9/70 to known clusters in contrast.
I mean there is an argument to be made that Victoria are testing too much if they have to delay results for days which means tracing and isolation is happening too late. Test results have to be timely if they want to actually be successful.
77 today and only 26 last Thursday.

And they've put their tally of community transmission up by 31-so much for it being good news the other day that it only went up by 6.
So the NT case was someone from Melbourne. Chances someone from Melbourne has taken it to Sydney? Has to be high.

Chances someone from Melbourne has taken it to regional Victoria? Almost certain, couldn't tell you where exactly though.
Qld Health Minister Miles - "it is possible that lock down will be extended to other postcodes".

Pretty much outright stating that Queensland thinks Victoria has not done enough.
For those who think that Victorian numbers have stabilised, you are trying to make that assumption too early.

Tokyo's last 6 days:

54
57
60
58
54
67

And then 107 today. Much better to act like your numbers are still going up until you have good evidence otherwise.
The ACT implements a quarantine for those from listed hot spots which totally ignores the reality that there are other post codes adding more cases per day at the moment that are not hot spots.

Greater Melbourne or Victoria is the hot spot, not these postcodes.
Well apparent number of Victorian cases is out, hardly a surprise. Two weeks ago it was 24 locally acquired cases announced.

Without more controls then it could be much higher in another 4 weeks.
The daily postcode announcement has really started. Inevitable that more postcodes will be locked down.

There is no stability in these numbers except for an upward direction.
7-day totals of locally acquired cases for Victoria:

June 06:20
June 13:16
June 20:78
June 27:153
July 04:506

Cases are rising, there is still no control-it is more out of control than ever.
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