Flights from China

[slats11]

What I'm more interested in knowing is how many of the Wuhan escapees who got out before the gate was shut are now in Oz.

Good question.For all intent and purpose, you can disregard the number in Hubei and Wuhan. They have run out of test kits and the number of infected has gone beyond the ability of the health system to diagnose and process, and that is assuming they’re not hiding the numbers.

The number in China but outside Hubei is the important thing. They can measure this, and person to person spread is well established. At present these numbers are doubling every two days. It is out of control. Despite the heads up from Wuhan

i have not seen any reason to believe the same will not apply outside China once person to person spread has become established.

And we have plenty from Wuhan. Eating out and catching flights with not a care in the world.

[vhtae]

I would assume that direct Cargo flights would be cancelled as well?

[Stickshift3000]

Originally Posted by Eclan

Chinese culture is paying for either an indulgence in eating raw bat and other things not meant to be consumed or a haphazard approach to their bio-warfare program safety. Take your pick.

More likely that bats (either wild or in captivity awaiting being cooked & eaten) have transmitted the virus to humans through faecal matter and poor human hygiene practices.

Bats are known to be very good virus reservoirs. There are many historic cases in Australia of bats spreading hantavirus (and other pathogens) through faecal matter into horse water troughs, which subsequently killed the horses. Obviously when viruses inevitably mutate some mutations can be far more deadly to humans.

[On eyre]

Not to trivialise the situation but a caller on Macca’s Australia All-over this morning suggested the virus should be given a common name - since Wuhan and Hubei were central to it’s origin he suggested it be named the WooHoo virus.

[Eclan]

Originally Posted by Stickshift3000

More likely that bats (either wild or in captivity awaiting being cooked & eaten) have transmitted the virus to humans through faecal matter and poor human hygiene practices.

Bats are known to be very good virus reservoirs. There are many historic cases in Australia of bats spreading hantavirus (and other pathogens) through faecal matter into horse water troughs, which subsequently killed the horses. Obviously when viruses inevitably mutate some mutations can be far more deadly to humans.

Yes I'm sure if you mess around with bat **** you'll also get sick but there's a lot of information out there that indicates they were also EATING bats and other animals from the food hall, market, whatever, which weren't really up to scratch and now they all have a disease.

[Stickshift3000]

Deep frying a bat will easily kill the sh!t out of any virus... just saying.

[PoppaJo]

Originally Posted by vhtae

I would assume that direct Cargo flights would be cancelled as well?

China Eastern and Air China still operating so the majority of freight will still be going I assume with these guys underneath.

Only China Southern, Xiamen are out of of now, and QF still a week to go

There is a few token direct cargo flights weekly from Sydney.

[slats11]

Wuhan city and Hubei province are likely dysfunctional, with a severe shortage of test kits and with a health system so overwhelmed that it no longer has the ability to diagnose and process new cases. Although Hubei reports 9,074 confirmed cases, total cases have been estimated to be 75,000.

Hence there is no point reviewing the data from Hubei. No one likely knows what is happening there anymore.

Likewise, there is little point looking at the total data as the vast majority of cases are still in Hubei (i.e. the total data is compromised by the uncertainty regarding Hubei).

Instead, it makes sense to look at the data from other mainland provinces. The epidemic is sufficiently established that there will be person-to-person spread, but the provinces should still have the ability to collect accurate data. We all accept Eclan's point that the data is subject to political interference. However we only have the data we have.

Anyway I looked at 7 different provinces, and looked at the number of cases reported at 0002 UTC 1st Feb, and compared it to the number of cases reported at 1021 UTC 2nd Feb (i.e. 34 hours later). On average over these 7 provinces, cases increased by 136% (from 2014 to 2731).

Put another way, 1/4 of cases now were not cases 34 hours ago.

Given this outbreak has been going on for several weeks, this dramatic increase over 34 hours can surely only be described as exponential.

[Double_Clutch]

I am hearing the evac flight May be going to LEA, not DRW.

[FlareArmed2]

Originally Posted by slats11

Anyway I looked at 7 different provinces, and looked at [two data points]...

...this dramatic increase over 34 hours can surely only be described as exponential.

Rubbish. It is mathematically impossible to establish an exponential function from only two data points. You have only described a linear function.

"Exponential" means a data series increases changes by x% each time period and requires more than two data points. In the absence of any quarantine or immunisation methods a typical contagious disease exhibits an exponential growth. Note the caveat: as soon as measures are taken to contain an outbreak the function is no longer exponential.

The very data series you quoted shows this (try this website from John Hopkins University for example, WHO has a similar page). Up to five days ago the series increased by roughly 50% per day. From four/five days ago the series increased by around 25% per day. You can see this in the data series for the total cases worldwide, the cases of Hubei province alone (which you claimed was false data) and the cases for China outside Hubei province (edited: not sure about outside China, too few data points to be certain). This is typical behaviour for a contagion showing that the extreme quarantine measures in China are having an effect.

And I do mean extreme. I live in Shanghai. No cars, taxis, or busses. No stores, banks or government buildings open. Only a few grocery stores with a handful of patrons. Nothing in the streets. It's eerie in a city of 28 million. Can you imagine this in Sydney, or London, or Tokyo? This has been going on for more than a week now, and given the median incubation period is about that, it should show up as a decline in the rate of increase of cases (note: a decline in the rate, not a decline in overall numbers).

Any statement that begins with the words "If the current trend continues..." is a lie. Try to avoid scaremongering and listen to reputable organisations such as WHO, CDC and so forth. There's a world of expertise out there.





"Cases" are number of cases reported in mainland China, from John Hopkins University.
Y-axis is plotted as a logarithm, so straight lines on graph show the exponential rate.
Coloured lines on chart show daily increase in number of cases reported.

[Winemaker]

Thanks FA2, I was going to generate a best fit equation for the data but you beat me to it. It's certainly not linear!

I sincerely hope that this isn’t a case of 3.6 roentgen in an infection sense due lack of test kits...

I sincerely hope this too, as adding radiation to the mix would really muck things up!

[Martin_Baker]

Originally Posted by Joker89

if they aren’t permanent residents they won’t be let in right?

You're probably right. I think the latest is no foreign nationals to be let in, only citizens and permanent residents.

The other reason for ceasing flights from the 9th February is the Chinese New Year festival runs from January 25th to February 8th. So AJ was probably keen on bringing home all those that went to China for the Lunar New Year.

[witwiw]

On average over these 7 provinces, cases increased by 136% (from 2014 to 2731).

The figures coming out are alarming enough but from 2014 to 2731 is an increase of 36%, not 136%.

[slats11]

Rubbish. It is mathematically impossible to establish an exponential function from only two data points. You have only described a linear function.

Correct up to a point. But this thing has been going on for weeks. If 25% of cases developed in last 34 hours, that's exponential enough for me under the circumstances.

And I do mean extreme. I live in Shanghai. No cars, taxis, or busses. No stores, banks or government buildings open. Only a few grocery stores with a handful of patrons. Nothing in the streets. It's eerie in a city of 28 million. Can you imagine this in Sydney, or London, or Tokyo? This has been going on for more than a week now, and given the median incubation period is about that, it should show up as a decline in the rate of increase of cases (note: a decline in the rate, not a decline in overall numbers).

No I can't imagine this in many places outside China.
Yesterday Wuhan announced that anyone showing symptoms of infection will be sent to dedicated isolation zone. To me, this confirms they can no longer test in Wuhan. If you look sick, you have the disease.
However banks and shops closed is why I have spent the weekend preparing.
It has been going on for much more than a week. It started back in December. The rapid increase in numbers and the rapid growth in containment measures the last 1-2 weeks is what is concerning.
The median incubation period is perhaps a week. But some cases definitely longer. And it is pretty clear that (unlike some other infectious), you are infectious before you are aware you are infected.

There's a world of expertise out there.

Indeed. Try this.
Lancet
This is the paper that estimated there were already 75,000 cases in Wuhan (as of last Tuesday). The authorities almost certainly do not have the ability to measure what is happening in Wuhan anymore.
This was the paper that led to the government over the weekend stopping people from China entering Aust (except citizens and PR). Note the reference to Sydney and Melbourne on page 5.
It calculated that epidemics are growing exponentially in multiple Chinese cities
It also concluded that large cities outside China with close transport links to China are at risk unless substantial measures are implemented immediately.

If the transmissibility of 2019-nCoV were similar everywhere domestically and over time, we inferred that epidemics are already growing exponentially in multiple major cities of China with a lag time behind the Wuhan outbreak of about 1–2 weeks.

It is these very experts using the word exponential.

Given that 2019-nCoV is no longer contained within Wuhan, other major Chinese cities are probably sustaining localised outbreaks. Large cities overseas with close transport links to China could also become outbreak epicentres, unless substantial public health interventions at both the population and personal levels are implemented immediately.

Look around Australia today and think whether we have implemented substantial public health interventions. Does stopping some direct flights next week constitute substantial and immediate?

Independent self-sustaining outbreaks in major cities globally could become inevitable because of substantial exportation of presymptomatic cases and in the absence of large-scale public health interventions. Preparedness plans and mitigation interventions should be readied for quick deployment globally.

Again, these calculations were done last week and published on 31 January.

We estimated that 75815 individuals (95% CrI 37304–130330) individuals had been infected in Greater Wuhan as of Jan 25, 2020.

[ACW562]

Speke or Hawarden

Question......Why not land at Speke or Hawarden. Minutes or so by road to Arrow Park Hospital. AND NO M6. Not that the residents of the Wirral are pleased no matter what they do.

[MickG0105]

Originally Posted by FlareArmed2

Rubbish. It is mathematically impossible to establish an exponential function from only two data points. You have only described a linear function.

Thank you! Wonderful to see someone else who understands the basics of mathematics and statistical analysis commenting on this.

[slats11]

The figures coming out are alarming enough but from 2014 to 2731 is an increase of 36%, not 136%.

Point taken. Increased by 36%. Or multiplied by 1.36 (or 136%).

But it seems we agree the figures are alarming.

[FlareArmed2]

Originally Posted by slats11

Correct up to a point ... It is these very experts using the word exponential.

We are in furious agreement. I also said it was exponential. What I objected to was that you calculated using two data points and claimed that this made the increase exponential. This is mathematically, scientifically and logically wrong. If you don't know why, don't make senseless calculations to draw conclusions that you don't understand. You're entitled to your opinions but not to the facts. Give up gracefully.

I had read the Lancet paper previously, a link to a non-pdf web version is here. You probably shouldn't quote selected sections of it when a more complete exert says differently. Example, you quoted this:

If the transmissibility of 2019-nCoV were similar everywhere domestically and over time, we inferred that epidemics are already growing exponentially in multiple major cities of China...

Whereas the paper goes on to say this:

Therefore, in the absence of (my emphasis) substantial public health interventions ... local establishment of epidemics might become inevitable. On the present trajectory, 2019-nCoV could be about to become a global epidemic in the absence of mitigation (my emphasis). Nevertheless, it might still be possible to secure containment of the spread of infection such that ... transmission does not lead to a large epidemic in locations outside Wuhan.

Which is also what I said: that a contagious disease spreads exponentially in the absence of any quarantine or immunisation methods. I even emphasised this.

I can't be bothered going further. Instead a few points about the Lancet paper (which is quite short and clear).

• They showed that there was a "negligible effect on epidemic dynamics" to restricting travel, with very little difference in spread comparing no travel restrictions to 50% travel restrictions (their Figure 4 and associated text); interesting. I wonder if this applies to the international travel bans as well.
• There are four caveats to the assumptions made in the paper that would affect outcomes; one of these was if there is any seasonality in the transmission of the virus, similar to influenza. I assume that If true this might have an effect on Australia in a few months.
• The assumptions on "cases" are different from the number of confirmed cases published by WHO, John Hopkins etc and used in my post and graph. This doesn't mean the Lancet paper is right and WHO is wrong, or vice versa. They are counting different things. The paper has an expandable panel showing the different definitions of "cases" used by CDC and the Lancet paper.
• The paper covers only cases from Dec 31 up until Jan 28, including the Wuhan travel ban that was instituted on Jan 23, so only five days of the Wuhan travel ban.

Your claim that the Lancet paper estimates 75,000 cases in Wuhan bears closer scrutiny. What they actually say is this:

In our baseline scenario, we estimated that R0 was 2·68 (95% CrI 2·47–2·86) with an epidemic doubling time of 6·4 days (95% CrI 5·8–7·1; figure 2). We estimated that 75 815 individuals (95% CrI 37 304–130 330) individuals had been infected in Greater Wuhan as of Jan 25, 2020.

For a start, the Lancet paper has a different definition of "cases" than the CDC (see above). Secondly, this is their "baseline scenario" it's not a prediction and it's not actual data. It's what they consider a reasonable baseline to use when comparing the effects of differing transmission rates and the effects of restrictions on travel. It may be close to the truth, or it may not. The confidence credible interval is very wide (approx -50% to +100%) which shows large changes in the number of cases follows relatively small changes in input.

Thirdly, this isn't necessarily bad news. If the epidemic doubling time is 6.4 days this is a daily increase of 11-12%, less than the daily estimates of 50% (during the same time period as the Lancet study) using CDC case numbers. Furthermore if c. 75,000 have been infected and the death rate is ~300 as at present, this is much better than current estimates of mortality.

This is typical of early stages of disease analysis: trying to estimate the numbers infected. Deaths are relatively easy to count but total infections, including asymptomatic cases, are much harder (impossible?) to count but must be estimated. A larger number of these hidden cases sounds more scary (infection rate is higher) but the consequences are less (mortality rate is lower). And so it goes...

[dragon man]

Update (1500ET): According to AFP, 20 French citizens evacuated from Wuhan, China have symptoms of Coronavirus. Earlier in the day, officials said that when the flight left Wuhan, none of the passengers had symptoms of coronavirus. They include French, Belgians, Dutch, Danes, Czechs, Slovaks and some citizens of African countries, the Associated Press reported. The happens as around 500 people, including hospital staff, form a human chain in front of the Robert Debré Hospital in Paris to denounce a lack of resources in French public hospitals

Frightening if correct.

[slats11]

We are in furious agreement. I also said it was exponential. What I objected to was that you calculated using two data points and claimed that this made the increase exponential. This is mathematically, scientifically and logically wrong.

So, you are agreeing that it is exponential, but just disagreeing with my method? Is that all we are disagreeing on?

Mathematically, yes you are correct. You can't prove an exponential relationship with just 2 points. But you can sure see something which hints at exponential.

Regardless, the 3rd point (which I respectfully suggest you are missing) is that this started before Christmas. There is no way you can have something start at zero 5 weeks ago, and increase by 25% in the last 34 hours without it being an exponential function.

That notwithstanding, I will update with the next provincial figures when they are made available - hopefully in the next few hours.

The incomplete figures thus far do not look promising.

Therefore, in the absence of (my emphasis) substantial public health interventions ... local establishment of epidemics might become inevitable. On the present trajectory, 2019-nCoV could be about to become a global epidemic in the absence of mitigation (my emphasis). Nevertheless, it might still be possible to secure containment of the spread of infection such that ... transmission does not lead to a large epidemic in locations outside Wuhan.

I agree with all that. There are a lot of "mights" in this

Do you see any substantial public health interventions?

The point is that we agree (I think) that it is currently exponential in China. Despite substantial interventions by China that would be very difficult to implement here. .

Where this ends? Who knows. Time will tell. Hopefully I am wrong. But for now, please lets be able to disagree without becoming disagreeable. Otherwise people simply disengage.