- JoNova - http://joannenova.com.au -

Corona virus and those exponential curves we don’t want

Posted By Jo Nova On February 1, 2020 @ 4:17 am In Global Warming,Health,Microbiology | Comments Disabled

Been trying to do a Corona thread for three days, but every time it was half finished everything changed.

The WHO have finally declared a state of emergency, something that seemed inevitable as soon as we knew the virus could be transmitted by people without symptoms. Russia, Mongolia, and North Korea closed their borders Thursday. Hong Kong announced a temporary closure. Singapore has now closed its borders too. Mark Steyn meanwhile, marvels that healthy US citizens are being advised not to go to China, but it’s apparently fine for sick people to travel the other way. Extraordinarily a cruise ship with 6,000 passengers was “stuck” off Italy, waiting for clearance for two Chinese people who had symptoms like a flu. Fortunately they must have just had the flu. The ship was cleared. And so it is around the world with a mosaic pattern of super actions, versus business as usual.

British Airways has suspended all flights to and from China, as have many other airlines, but in a city by city way.  The virus is now present in every region of China. It’s not clear why all flights to and from China have not been stopped. On ABC news Australia’s supposedly top medico didn’t explain why, just palmed off the decision as advice from the WHO. Red flags anyone? A union of pilots in the US is so concerned they are suing American Airlines in a bid to stop them flying there to protect crews. They are calling for staff to refuse work trips to high-risk locations. On #CoronaOutbreak there are photos of shelves emptying in Shanghai, people are wearing giant juice bottles on their heads, and not wearing a face mask is considered a bad thing — indeed, people are being arrested for not wearing face masks. Videos apparently show people being forcibly locked inside houses because of their suspected infections.

The first case of human to human transmission has been confirmed in the US and 168 people are now on a watchlist. Passengers on one flight in Australia have just been advised they were travelling on Monday night with a man who has been diagnosed. 200 people are being contacted. The plane flew another 13 legs or so before it got a proper clean and that contact list might, yeah, well… The sick man was part of a group of eight who toured the risky part of China, four of the eight have symptoms and all eight are in isolation.

The live map and official Corona Virus tally (for whatever that means) is 213 deaths and 9,776 confirmed infections, plus or minus 2,000 or 80,000 (Uni HK below). But 100 or so cases are now confirmed outside China, so we are on the cusp of a global epidemic.

And yes, apparently, before that even happens, the Climate Doomsters are already predicting Climate Change will increase the odds of the next one. Never let a good crisis go to waste. h.t Pat

Coronavirus, 2019-CoV, graph, map.

John Hopkins CSSE…Live Map 31-Jan-2019

Ominously, the “total officially recovered”, is just 187 — by this tally, more have died than survived. But this is probably just a measure of those who got the most severe form of the disease and also managed to survive an overcrowded and underfunded Chinese ICU. Added to this, Wuhan is an industrial town with heavy air pollution –  known as “the Chicago of China” or China’s Smog City. That can’t be too good for local lungs.  The guesstimate on the BBC is that about a quarter of people get “the bad form”.

It’s likely that many other people have already caught this in China, but didn’t get deadly sick, and didn’t go to hospital and are not counted here at all. The virus may even cause subclinical, or low grade barely detectable disease in some, though in this world of unknowns,  there are undoubtedly other deaths that may not be included in the tally too — misdiagnosed or undiagnosed and just rushed to the crematorium.

WHO says the death rates are 2% though no one really knows. A recent paper in Lancet estimates 11%. The fact is, there are no facts we can rely on. (h.t Mishtalk) But if that Lancet paper is closer to the mark, there is a gargantuan trainwreck coming. Quick, someone explain exponential curves to the people in power. We need to act like lightning to head this off.

Some estimate put the number of people infected at tens of thousands higher (see estimates below). It did seem odd that a city of 11 million suddenly needed new “2-minute-hospitals” to cope with a few thousand patients. Someone knew something. Indeed, there are many fishy things about this, including those fish markets which may or may not be the source. There is that odd coincidence of China’s first high level biosafety laboratory being also in Wuhan and working with Corona viruses as well as Ebola and SARS. There were warnings.

Below is the official trajectory. What we really want to see on this graph below is any kind of leveling off. Instead, we see 1000 become 10,000 in a week. And the more people infected, the more opportunity for mutations. And if there are wildlife vectors, it will run amok and stick around.

2019 CoV, coronavirus, graph, statistics.

John Hopkins CSSE…Live Map 31-Jan-2019

Here’s hoping…

Communist governments aside, the Chinese people are smart enough and motivated to slow things themselves. Social media and the rapid spread of fear is driving people to isolate themselves, so the epidemic may plateau sooner and lower than the worst projections. There is action. Some towns and even apartment blocks are getting organised and cutting themselves off. As long as people can stay inside and avoid public gatherings long enough, it will help.

The rate of spread

Estimates of the Ro or Reproductive number are in the 2 – 3 range (or lately 1.4 – 2.5) but changing fast.  An Ro of 2 means one person is likely to infect 2 others, which makes it on par with influenza in terms of spreadability (and thus “stoppability” once it has gained a foothold).

Ro examples: Ebola, 1.5 – 2.5; Influenza 2 – 3; Munps 4 – 7; Polio and Smallpox 5 – 7;  Measles 12 – 18.

Obviously Ro matters: Bigger numbers mean faster, higher peaks. Without intervention, the number starts to flatten when enough people are immune through having had it and recovered. Alternately, careful tracing of contacts with vaccination can slow the spread sooner. I’m guessing that even a vaccine with a short lived efficacy would slow transmission and be useful in an emergency situation.

Ro, Reproductive curves, graph, infectious diseases.

Ro, Reproductive curves of  infectious diseases. ResearchGate

Obviously an Ro of 1 or less means a disease will shrink away to nothing. So if quarantine measures are strong enough, and the effective Ro can be reduced, infections will plateau and shrink. But it will take aggressive and quick action to achieve that. Exponential curves are so unforgiving.

Doubling every 6 days?

The University of Minnesota Center for Infectious Disease Research and Policy (CIDRAP) reported on Jan 27th that the 2019-nCoV spread in China’s cities could trigger a global epidemic.

…experts from the University of Hong Kong (HKU) estimated that the number of cases in Wuhan as of Jan 25 was dramatically higher than the country’s official totals and may be as high as 44,000. They also estimated that the city’s cases will double over the next 6 days.

They said that about 25,000 people in Wuhan are likely symptomatic and the others are still in the incubation period.

Note that other estimates are very different (eg Uni of Lancashire = 11,000)

Estimates of Ro, CoronaVirus, Jan 25th, 2020.  Graph.

Estimates of epidemic spread, CoronaVirus, Jan 25th, 2020  |Mishtalk

They estimate the peak in China will not occur until April or May.  That is a lot of doublings away…

Based on outbreak data and train, air, and road travel from Wuhan—which is central China’s transportation hub—they said Chongqing could be the next most affected city, because of its strong transport ties to Wuhan. They said outbreaks in Chongqing, Beijing, Shanghai, Guangzhou, and Shenzhen could peak in April or May and gradually slow in June and July.

With 8 to 12 doublings til the peak in China, if there are 80,000 infections now, in six weeks there could be 5 million. In 8 weeks 20 million, and in 12 weeks 320 million. If there are only 10,000 now, it may mean the same thing with a three-week delay. But that three weeks could make a huge difference to the final tally if the rate of doubling can be slowed aggressively now. Every day counts.

These estimates are jelly in every sense. The official graph from the John Hopkins live map above suggests the doubling time is much faster than 6 days.

What do you do in a lockdown?

Let’s not forget that in Wuham there are millions of healthy people (and we hope as many as possible stay that way).


The Simpsons do it again:

Chiefio has two threads with further discussion here and here.

With a comment from Larry Ledwick who says:

29 January 2020 at 8:56 pm

More on the use of existing drugs to suppress 2019-nCoV infections.


Chinese researchers have found three existing drugs with fairly good inhibitory effects on the novel coronavirus (2019-nCoV) at the cellular level, a local newspaper has reported.

The three drugs are Remdesivir, Chloroquine and Ritonavir. They are now under relevant procedures to gain approval for clinical use, said Hubei Daily on Wednesday.

Lastly: :- )

VN:F [1.9.22_1171]
Rating: 9.6/10 (62 votes cast)

Article printed from JoNova: http://joannenova.com.au

URL to article: http://joannenova.com.au/2020/02/corona-virus-and-those-exponential-curves/

Copyright © 2008 JoNova. All rights reserved.